How to parse Twitter search result with iOS NSJSONSerialization in a UITableView? - iphone

I'm having trouble parsing a Twitter search result with the built in iOS JSON parser.
NSDictionary *resultorig = [NSJSONSerialization JSONObjectWithData:self.responseData options: NSJSONReadingMutableContainers error: &err];
NSMutableArray *result = [resultorig objectForKey:#"results"];
NSLog(#"%#", result);
I'm searching Twitter with this url: http://search.twitter.com/search.json?q=%23xbox
in which prints out:
{"completed_in":0.013,"max_id":288030748135530498,"max_id_str":"288030748135530498","next_page":"?page=2&max_id=288030748135530498&q=%23xbox","page":1,"query":"%23xbox","refresh_url":"?since_id=288030748135530498&q=%23xbox","results":[{"created_at":"Sun, 06 Jan 2013 21:14:16 +0000","from_user":"momarkmagic","from_user_id":41954598,"from_user_id_str":"41954598","from_user_name":"Mark Molnar","geo":null,"id":288030748135530498,"id_str":"288030748135530498","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/342500438\/avat_normal.jpg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/342500438\/avat_normal.jpg","source":"<a href="http:\/\/twitter.com\/">web<\/a>","text":"RT #conceptartworld: Check out Halo 4 Concept Art by Thomas Scholes! http:\/\/t.co\/JdDr40XM #xbox #illustration http:\/\/t.co\/AKjZGKgN","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:14:07 +0000","from_user":"DeJesusRaymond","from_user_id":57501625,"from_user_id_str":"57501625","from_user_name":"Raymond DeJesus\u0950","geo":null,"id":288030711229861888,"id_str":"288030711229861888","iso_language_code":"da","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3069994571\/4b2761d7571bb012354f7efd47c71eb2_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3069994571\/4b2761d7571bb012354f7efd47c71eb2_normal.jpeg","source":"<a href="http:\/\/instagr.am">Instagram<\/a>","text":"#360 #xbox #swag #thuglife. http:\/\/t.co\/Q0mteFMA","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:13:59 +0000","from_user":"ShotzLiam_3","from_user_id":598301611,"from_user_id_str":"598301611","from_user_name":"Liam","geo":null,"id":288030679453798400,"id_str":"288030679453798400","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/2866443960\/9c7349d8672774cae56aedfcc1955b31_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/2866443960\/9c7349d8672774cae56aedfcc1955b31_normal.jpeg","source":"<a href="http:\/\/twitter.com\/download\/iphone">Twitter for iPhone<\/a>","text":"#FifaaGiveaways can I have some coins #xbox","to_user":"FifaaGiveaways","to_user_id":943979888,"to_user_id_str":"943979888","to_user_name":"Free UT Giveaways"},{"created_at":"Sun, 06 Jan 2013 21:13:28 +0000","from_user":"Kuvaga","from_user_id":83686315,"from_user_id_str":"83686315","from_user_name":"Kut V. \u26a1","geo":null,"id":288030544850206720,"id_str":"288030544850206720","iso_language_code":"es","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3060318139\/af19b6a35cdf09e4f54e12835e18093e_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3060318139\/af19b6a35cdf09e4f54e12835e18093e_normal.jpeg","source":"<a href="http:\/\/twitter.com\/download\/iphone">Twitter for iPhone<\/a>","text":"Este es el que te dije #GarcIA_MGM #Xbox http:\/\/t.co\/04N9fESH","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:13:24 +0000","from_user":"benzybk","from_user_id":275588581,"from_user_id_str":"275588581","from_user_name":"Benzy Babykutty","geo":null,"id":288030531063541762,"id_str":"288030531063541762","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3040249039\/d741b8ccfdb9d130be72eadd77471adc_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3040249039\/d741b8ccfdb9d130be72eadd77471adc_normal.jpeg","source":"<a href="http:\/\/twitter.com\/download\/iphone">Twitter for iPhone<\/a>","text":"RT #TheSunNewspaper: The next Xbox versus the PS4, we take a look at what to expect. http:\/\/t.co\/SdFzZUYv #xbox #ps3 #gaming","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:13:13 +0000","from_user":"Lewis_Whitfield","from_user_id":53468672,"from_user_id_str":"53468672","from_user_name":"ImLatchingOntoYou.","geo":null,"id":288030482623516672,"id_str":"288030482623516672","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3008431805\/15b78d1e299047711e5ab6da0cbe3e28_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3008431805\/15b78d1e299047711e5ab6da0cbe3e28_normal.jpeg","source":"<a href="http:\/\/instagr.am">Instagram<\/a>","text":"Completed Forza Horizon! Yay #xbox #xbox360 #forza #completed #sad #intense #best #game #ever http:\/\/t.co\/AedVwph0","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:12:51 +0000","from_user":"sexyboy529","from_user_id":394412198,"from_user_id_str":"394412198","from_user_name":"Sexyboy","geo":null,"id":288030392844435456,"id_str":"288030392844435456","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/sticky\/default_profile_images\/default_profile_5_normal.png","profile_image_url_https":"https:\/\/si0.twimg.com\/sticky\/default_profile_images\/default_profile_5_normal.png","source":"<a href="http:\/\/twitter.com\/">web<\/a>","text":"RT #Sam_James96: My life is dedicated to xbox today. #xbox #GTA5","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:12:28 +0000","from_user":"Andreact93","from_user_id":211217957,"from_user_id_str":"211217957","from_user_name":"Andrea Gazzo","geo":null,"id":288030296312537090,"id_str":"288030296312537090","iso_language_code":"da","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/1771937572\/foto_twitter_normal.jpg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/1771937572\/foto_twitter_normal.jpg","source":"<a href="http:\/\/instagr.am">Instagram<\/a>","text":"#xbox360 #controller #game #halo4 #games #gamers #xbox #modded #led #blue http:\/\/t.co\/bTkCuyT0","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:12:24 +0000","from_user":"2xMolly2xBlunt","from_user_id":259448291,"from_user_id_str":"259448291","from_user_name":"\u2665Rihanna\u2665BabyDaddy\u2665\ue420","geo":null,"id":288030277299736577,"id_str":"288030277299736577","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/2956632635\/442f652a4e993f26d285e80ccb57910a_normal.png","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/2956632635\/442f652a4e993f26d285e80ccb57910a_normal.png","source":"<a href="http:\/\/twitter.com\/">web<\/a>","text":"Time to play 2k who wanna play #RT #2K13 #XBOX","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:12:23 +0000","from_user":"_kdog","from_user_id":118113755,"from_user_id_str":"118113755","from_user_name":"Kirsten Thomson","geo":null,"id":288030276670611458,"id_str":"288030276670611458","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3061762292\/c8d1047d30ab44a6ee922500bce85370_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3061762292\/c8d1047d30ab44a6ee922500bce85370_normal.jpeg","source":"<a href="http:\/\/instagr.am">Instagram<\/a>","text":"I love skyrim so much. #skyrim #Lynda #Clyde #ilovewater #xbox #sarahando http:\/\/t.co\/bM2dSIkZ","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:12:10 +0000","from_user":"ReeceAxten","from_user_id":405803362,"from_user_id_str":"405803362","from_user_name":"ReeceAxten\u00ae","geo":null,"id":288030220164952064,"id_str":"288030220164952064","iso_language_code":"tl","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3074248109\/0fa728912afd324e8722169c4efc3ab2_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3074248109\/0fa728912afd324e8722169c4efc3ab2_normal.jpeg","source":"<a href="http:\/\/twitter.com\/download\/iphone">Twitter for iPhone<\/a>","text":"Fifa anyone? #xbox","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:11:02 +0000","from_user":"karlheath6","from_user_id":984240522,"from_user_id_str":"984240522","from_user_name":"Karl heath","geo":null,"id":288029933144518657,"id_str":"288029933144518657","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3007892972\/4988eca8a918c2fa1b28b48d0f0980df_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3007892972\/4988eca8a918c2fa1b28b48d0f0980df_normal.jpeg","source":"<a href="https:\/\/mobile.twitter.com">Mobile Web (M2)<\/a>","text":"RT #Retroshock316: For a chance 2 win #DirtShowdown for #Xbox, follow #Retroshock316 + RT this. Winner announced when we hit 2k followers. #Comp #Competition","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:10:45 +0000","from_user":"SWARNERx","from_user_id":244070634,"from_user_id_str":"244070634","from_user_name":"- Shell Warner\u2717","geo":null,"id":288029861786820609,"id_str":"288029861786820609","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/3071322789\/ba7c82da179f851fea6a4a12ad66c0bd_normal.jpeg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/3071322789\/ba7c82da179f851fea6a4a12ad66c0bd_normal.jpeg","source":"<a href="http:\/\/twitter.com\/">web<\/a>","text":"back to #xbox .#Blackops2 add me : SWARNERx . #Zombies.","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:10:26 +0000","from_user":"headshotcola","from_user_id":1064288336,"from_user_id_str":"1064288336","from_user_name":"Xbox_Headshotcola","geo":null,"id":288029783584022528,"id_str":"288029783584022528","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/sticky\/default_profile_images\/default_profile_6_normal.png","profile_image_url_https":"https:\/\/si0.twimg.com\/sticky\/default_profile_images\/default_profile_6_normal.png","source":"<a href="http:\/\/twitter.com\/download\/android">Twitter for Android<\/a>","text":"People buy #ForzaHorizon it is such a good game best racing game you would #xbox","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null},{"created_at":"Sun, 06 Jan 2013 21:10:15 +0000","from_user":"joecurry281186","from_user_id":338231824,"from_user_id_str":"338231824","from_user_name":"Joe Curry","geo":{"coordinates":[52.092676,-1.836255],"type":"Point"},"id":288029737761263616,"id_str":"288029737761263616","iso_language_code":"en","metadata":{"result_type":"recent"},"profile_image_url":"http:\/\/a0.twimg.com\/profile_images\/2402359791\/image_normal.jpg","profile_image_url_https":"https:\/\/si0.twimg.com\/profile_images\/2402359791\/image_normal.jpg","source":"<a href="http:\/\/twitter.com\/download\/iphone">Twitter for iPhone<\/a>","text":"Just deleted a load of content to install FableIII and its still running like crap #xbox #ffs","to_user":null,"to_user_id":0,"to_user_id_str":"0","to_user_name":null}],"results_per_page":15,"since_id":0,"since_id_str":"0"}
I"m trying to display the tweet text in each row of the tableview but it crashes with my current code:
NSDictionary *aTweet = [result objectAtIndex:indexPath.row];
cell.theTweet.text = [aTweet objectForKey:#"text"];
NSLog(#"%#", [aTweet objectForKey:#"text"]);
What am I doing wrong? Any help would be appreciated because I've spent almost all day trying to fix this crash. Thanks.


I figured it out finally. It was in the parsing of the tree. I was parsing it incorrectly. I needed to loop through the tree as follows:
for (NSDictionary *newDictionary in result) {
NSString *tweetNew = [newDictionary objectForKey:#"text"];
}


The JSON Response you are obtaining is valid. So in usual situations there should not be any problems in parsing it.
Personally I am a fan of SBJson for JSON parsing. Please refer this link
http://stig.github.com/json-framework/
Its good if you can map the in coming data to model classes. To map data to model classes you can make use of any KVC wrappers.
Hope this helps.

Related

How can i ParseExact Wed Jun 27 08:50:00 2018 -0500

Im trying to use [datetime]::ParseExact
The string i need to convert to datetime is Wed Jun 27 08:50:00 2018 -0500
I couldnt figure out the correct format to convert it correctly.
Please help me out. Thanks

Try this as well:
$Date = 'Wed Jun 27 08:50:00 2018 -0500'
[datetime]::ParseExact($Date,"ddd MMM dd HH:mm:ss yyyy zzz",[CultureInfo]::InvariantCulture)

There are several options. To some extent it will depend on what you want to do with that time offset. Here is one way that ignores the offset:
$test = 'Wed Jun 27 08:50:00 2018 -0500'
$parts = $test.split(' ')
$date = get-date ('{0}{1}{2} {3}' -f $parts[2], $parts[1], $parts[4], $parts[3])

Change date format 08 / 03 / 2017 to 08 March 2017

I'm trying to change date format from 08/03/2017
08 day
03 Month
2017 year
I I'm using
date("d F Y", strtotime($date));
the problem is that I Get 03 August 2017 instead of 08 March 2017
PS : I can't use any other then
dd/mm/yyyy

Try this
$date = DateTime::createFromFormat('d/m/Y', "08/03/2017");
echo $date->format('d F Y');
You can check it to http://php.net/manual/en/datetime.createfromformat.php

After Some researchs I found a solution
str_replace(' / ', '-',$date)

/*
You got August because you provide wrong format to this function. Function accept m/d/y and you provide d/m/y. you can try with this format m/d/y
or
you can try this with DateTime object.
*/
$date = "08/03/2017";
$dateObject = DateTime::createFromFormat('d/m/Y', $date);
echo $dateObject->format('d M Y');

Dealing with (birthday) dates and Timezone with Dojo

I have a simple widget that has:
<input class="input" id="${id}_dateOfBirth" name="dateOfBirth" data-dojo-type="dijit/form/DateTextBox" />
Note that it's a birthday. So, it's meant to stay the same, regardless of where you are when you are (timezone shouldn't happen). If you are born on the 10th of January at 3:00AM in England, and view your personal information from New York, you are meant to still see 10th of January, NOT the 9th!
I am in GMT+8 right now.
When I submit this form, this actually gets to the server when I put in 1/1/1970:
dateOfBirth: "1969-12-31T16:00:00.000Z"
Which is bad, because it's 8 hours short of the actual date.
Basically, I need a way for the DateTextBox to show the date as it came from the server, effectively ignoring the browser's timezone.

FWIW, here is my variant of UTCDateTextBox:
define([
"dojo/_base/declare",
"dijit/form/DateTextBox"
], function(declare, DateTextBox) {
function isValidDate(value) {
return value instanceof Date && isFinite(value.getTime());
}
function toUTCDate(value) {
if (isValidDate(value)) {
value = new Date(
Date.UTC(value.getFullYear(), value.getMonth(), value.getDate())
);
}
return value;
}
return declare(DateTextBox, {
_getValueAttr : function() {
return toUTCDate(this.inherited("_getValueAttr", arguments));
}
});
});
For my use case, I found that I didn't need to override _setValueAttr(). With the above implementation, when getUTCXXX(), toUTCString(), toISOString() or toJSON() are called on the date object returned from _getValueAttr(), then the correct UTC date with zeroed time elements is returned.
Hope this helps.

After much hacking and analysing Dojo's source code, I came up with this:
var UTCDateTextBox = declare( 'UTCDateTextBox', [ DateTextBox ], {
_getValueAttr: function(){
var ov = this.inherited(arguments);
if( ov ){
ov.setTime( ov.getTime() - ov.getTimezoneOffset() * 60 * 1000 );
}
return ov;
},
_setValueAttr: function( value, priorityChange, formattedValue){
var v = stamp.fromISOString( value );
if( v ){
v.setTime( v.getTime() + v.getTimezoneOffset() * 60 * 1000 );
value = v;
}
this.inherited(arguments);
}
});
Basically:
When the value is set, the timezone difference gets added. This means that if the server has 1979-12-25T00:00:00.000Z, rather than assigning Tue Dec 25 1979 08:00:00 GMT+0800 (WST), it will assign Tue Dec 25 1979 00:00:00 GMT+0800 (WST) . Basically, the date is converted locally to whatever it was in UTC.
When the value is parsed, it will be changed from Tue Dec 25 1979 00:00:00 GMT+0800 (WST) to Tue Dec 25 1979 08:00:00 GMT+0800 (WST)
The changed value is the one submitted to the server. So, it will be correct regardless of what timezone it will be edited at.
Since I only ever ever deal with dates, if the server has 1979-12-31T23:00:00Z (which is an error: for birthdays, the time is actually ignored and mustn't matter), this will happen:
When the value is set, ISO is 1979-12-31T23:00:00.000Z. So, Tue Jan 01 1980 07:00:00 GMT+0800 (WST) is changed into Mon Dec 31 1979 23:00:00 GMT+0800 (WST). This means that the right date is placed into the date textbox (31/12/1979).
When the value is parsed from the textbox, Mon Dec 31 1979 00:00:00 GMT+0800 (WST) becomes Mon Dec 31 1979 08:00:00 GMT+0800 (WST). So, the server will save 1979-12-31T00:00:00Z -- which is, again, the correct date!
If there are bettere solutions, please let me know. Frankly, I hope there are as this one feels like a bit of a cheat!

JSON Parsing not giving Proper NSMutable Array :

I am working on one Webservice app .
They give me response like :
JSON RESPONSE:
{"1":"03:30 PM To 04:30 PM","2":"01:30 PM To 02:30 PM","3":"02:30 AM
To 03:30 PM","4":"04:30 PM To 05:30 PM","5":"05:30 PM To 06:30
PM","6":"06:30 PM To 07:30 PM"}
And I want to Show all this TIME intervel with Check box in my another View controller so User can select it .
How do I get this ...
Need help

Check out the documentation for NSArray componentsSeparatedByString:(NSString *). This will separate the Json reply into an array at the string you specify. I would probably use #",".

You can use SBJson classes to parse json data,
here is the like to get all classes
SBJson

You can simply parse the JSON by following Method
NSString* strJSONResponse = #"{\"1\":\"03:30 PM To 04:30 PM\",\"2\":\"01:30 PM To 02:30 PM\",\"3\":\"02:30 AM To 03:30 PM\",\"4\":\"04:30 PM To 05:30 PM\",\"5\":\"05:30 PM To 06:30 PM\",\"6\":\"06:30 PM To 07:30 PM\"}";
NSDictionary* dataDict = [strJSONResponse JSONValue];
NSLog(#"%#",dataDict);
Here is the output:
Printing description of dataDict:
{
1 = "03:30 PM To 04:30 PM";
2 = "01:30 PM To 02:30 PM";
3 = "02:30 AM To 03:30 PM";
4 = "04:30 PM To 05:30 PM";
5 = "05:30 PM To 06:30 PM";
6 = "06:30 PM To 07:30 PM";
}
With this dictionary you can simply make use as per your requirement.
Here you will need to include Required classes for SBJSON found here
I had to add "\" as an escape characters to use it as a string.
Hope it helps

How do I set the timezone for Perl's localtime()?

In Perl, I'd like to look up the localtime in a specific timezone. I had been using this technique:
$ENV{TZ} = 'America/Los_Angeles';
my $now = scalar localtime;
print "It is now $now\n";
# WORKS: prints the current time in LA
However, this is not reliable -- notably, if I prepend another localtime() call before setting $ENV{TZ}, it breaks:
localtime();
$ENV{TZ} = 'America/Los_Angeles';
my $now = scalar localtime;
print "It is now $now\n";
# FAILS: prints the current time for here instead of LA
Is there a better way to do this?

Use POSIX::tzset.
use POSIX qw(tzset);
my $was = localtime;
print "It was $was\n";
$ENV{TZ} = 'America/Los_Angeles';
$was = localtime;
print "It is still $was\n";
tzset;
my $now = localtime;
print "It is now $now\n";
$ perl -v
This is perl, v5.8.8 built for x86_64-linux-thread-multi
Copyright 1987-2006, Larry Wall
Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.
Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl". If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.
$ perl tzset-test.pl
It was Wed Apr 15 15:58:10 2009
It is still Wed Apr 15 15:58:10 2009
It is now Wed Apr 15 12:58:10 2009

I'd strongly suggest using a module to do this. Specifically, I'd suggest using DateTime (see Perl DateTime Wiki or CPAN
Then you should be able to do something like the following:
use strict;
use warnings;
use DateTime;
my $dt = DateTime->now(); # *your* local time assuming your system knows it!
my $clone1 = $dt->clone; # taking a copy.
$clone1->set_time_zone('America/Los_Angeles');
print "$clone1\n"; # output using ISO 8601 format (there a lot of choices)
print "$dt\n";

Whilst your code works fine for me on both Linux (Perl 5.10.0) and MacOS X (5.8.9), there is a possible solution.
The underlying C functons used by Perl (ctime(), localtime(), etc) call tzset() the first time they're invoked, but not necessarily afterwards. By calling it yourself you should ensure that the timezone structures are correctly re-initialised after any change to $TZ.
Fortunately this is easy - the tzset() function is available in the POSIX module:
#!/usr/bin/perl -w
use POSIX qw[tzset];
$ENV{'TZ'} = 'Europe/London';
tzset();
print scalar localtime();
NB: some Google searches suggest that this is only necessary with Perl versions up to and including 5.8.8. Later versions always call tzset() automatically before each call to localtime().

use Time::Zone;
my $TZ = 'America/Los_Angeles';
my $now = scalar localtime time() + tz_offset($TZ);
print "It is now $now\n";
seems to work here. (The 'scalar' is redundant here since $now gives it scalar context, but it's also nice to be explicit.)
As per the comment, I got the original problem. This seems to fix it for me, but given that others aren't having the original problem, the "seems to work here" bit is intended as an invitation for those people to try this solution as well to ensure it doesn't break anything. (I have to wonder if alnitak noticed the difference between what I posted and the original post?)

Expanding on BrianP007 answer you use both TZ and _tzset
$was = localtime;
print "It was $was\n";
$ENV{TZ} = 'CST6CDT'; # America/Chicago
Time::Piece::_tzset(); # Local time is now Chicago Time
$was = localtime;
print "It is $was\n"; # Right now in Chicago
The trick is the TZ is set from your location to GMT. So normally you would think Chicago is UTC-6, but from Chicago it is 6 hours to UTC which = 'CST6'.
See http://science.ksc.nasa.gov/software/winvn/userguide/3_1_4.htm

Executive Summary:
Setting $ENV{TZ}='/*&+000000000005' and calling Time::Piece::_tzset() fixes localtime() to agree with the windoz system clock.
Sanguinarily gory details:
On Strawberry Perl, windoz 7/64, none of the "Standard" time zones works in the TZ environmental variable to localize localtime(). 'America/Chicago' gives exactly the same time as 'America/Los_Angeles' == 'CDT' == 'CST' == 'UTC' == '-01:00', etc. The list is infinite.
Every timezone on http://www.timeanddate.com/time/zones/ that I tried gives the right time if you are in Greenwich.
Every time from: http://en.wikipedia.org/wiki/List_of_tz_database_time_zones
also fails to change localtime() at all. And, there is no apparent indication. They do nothing and say nothing.
There is NO tzset() on windoz:
POSIX::tzset not implemented on this architecture
There is not even any concept of POSIX ???
C:\bin>cpan install POSIX
...
Warning: Cannot install POSIX, don't know what it is.
Try the command i /POSIX/
It appears to be baked into win8 and there are some dot NOT libraries for it.
For Austin, Texas, in the very Center of Central Intergalactic Time, thee correct $ENV{TZ} which gives me a scalar localtime() which ~agrees with the o/s level time function and the windoz clock is:
'/*&+5' !!! Yes Slash-Star-Ampersand-Plus-5 works!
P:\br1\sxsw.2015\sx-2015.0318\done>time
The current time is: 16:36:39.44
...
Time=Apr 14 16:36:42 2015, ENV->TZ=/*&+5
By running a for loop and trying random values from various posts, for Strawberry Perl uname='Win32 strawberry-perl 5.18.2.2...' with known timezone bugs, any 3 chars I tried (didn't try + or -) followed by +/- and a small number worked. Here is an array of text values and their output below:
use Time::Piece;
#tz = ('', 'CDT+5', 'CST+5', 'FKU+5', 'XYZ+5', '+5', '+05', '+05.00',
'America/Chicago', 'America/Los_Angeles', 'CDT',
'CST', 'UTC', 'PDT', 'PST', '-01:00', '+01:00', '-05:00'.
'ACDT', 'EASST', '5000', '+0500', '+5:00', '+05:00', 'SSS+1', 'SSS+0',
'zzz-1', 'ZZ1+5', '123+5', '___+5', '/*&+5', , '/*&+05', '/*&+005',
'/*&+000000000005');
foreach $tz (#tz) {
$ENV{TZ} = $tz if $tz;
Time::Piece::_tzset() if $tz;
printf("T%s, ENV->TZ=%s\n", scalar localtime, $ENV{TZ} || 'NoTZ');
}
Most every try with anything but XXX . +|- . integer gave UTC, but many were an hour off for no reason (America/Los_Angeles and America/Chicago gave the same value). I am almost sure I used to get away with just CDT and CST, possibly on Activestate (switched to Strawberry to compile my own Perl modules rather than rely on Activestate for everything). This is the first major snarl.
I rebuilt DateTime from scratch and it worked fine. DateTime::TimeZone::Local::Win32 "failed for 'Win32::TieRegistry'"
Here's the sorted result of the attempted zones above:
P:\br1\sxsw.2015\sx-2015.0318\done>bb | sort
Running c:/bin/bb.pl Tue Apr 14 21:43:56 2015
TTue Apr 14 16:43:56 2015, ENV->TZ=/*&+000000000005
TTue Apr 14 16:43:56 2015, ENV->TZ=/*&+005
TTue Apr 14 16:43:56 2015, ENV->TZ=/*&+05
TTue Apr 14 16:43:56 2015, ENV->TZ=/*&+5
TTue Apr 14 16:43:56 2015, ENV->TZ=___+5
TTue Apr 14 16:43:56 2015, ENV->TZ=123+5
TTue Apr 14 16:43:56 2015, ENV->TZ=CDT+5
TTue Apr 14 16:43:56 2015, ENV->TZ=CST+5
TTue Apr 14 16:43:56 2015, ENV->TZ=FKU+5
TTue Apr 14 16:43:56 2015, ENV->TZ=XYZ+5
TTue Apr 14 16:43:56 2015, ENV->TZ=ZZ1+5
ABOVE ALL WORKED Below most failed with UTC or +1 hour???
TTue Apr 14 20:43:56 2015, ENV->TZ=SSS+1
TTue Apr 14 21:43:56 2015, ENV->TZ=-01:00
TTue Apr 14 21:43:56 2015, ENV->TZ=+01:00
TTue Apr 14 21:43:56 2015, ENV->TZ=+05
TTue Apr 14 21:43:56 2015, ENV->TZ=+05:00
TTue Apr 14 21:43:56 2015, ENV->TZ=+0500
TTue Apr 14 21:43:56 2015, ENV->TZ=+5
TTue Apr 14 21:43:56 2015, ENV->TZ=+5:00
TTue Apr 14 21:43:56 2015, ENV->TZ=5000
TTue Apr 14 21:43:56 2015, ENV->TZ=CDT
TTue Apr 14 21:43:56 2015, ENV->TZ=CDT
TTue Apr 14 21:43:56 2015, ENV->TZ=CST
TTue Apr 14 21:43:56 2015, ENV->TZ=PDT
TTue Apr 14 21:43:56 2015, ENV->TZ=PST
TTue Apr 14 21:43:56 2015, ENV->TZ=SSS+0
TTue Apr 14 21:43:56 2015, ENV->TZ=UTC
TTue Apr 14 22:43:56 2015, ENV->TZ=-05:00ACDT
TTue Apr 14 22:43:56 2015, ENV->TZ=+05.00
TTue Apr 14 22:43:56 2015, ENV->TZ=America/Chicago
TTue Apr 14 22:43:56 2015, ENV->TZ=America/Los_Angeles
TTue Apr 14 22:43:56 2015, ENV->TZ=EASST
TTue Apr 14 22:43:56 2015, ENV->TZ=zzz-1
Even after finding and installing the Holy Grail, the TzFile module for the Olsen Database, it is still screwed, no difference!
Installing C:\bin\strawberry_perl_5_18\perl\site\lib\DateTime\TimeZone\Tzfile.pm
ZEFRAM/DateTime-TimeZone-Tzfile-0.010.tar.gz
C:\bin\strawberry_perl_5_18\perl\bin\perl.exe ./Build install --uninst 1 -- OK
Here are all of the alleged timezones which do nothing on this platform from:
#atz = DateTime::TimeZone->all_names();
printf("All tz names [%d] = %s\n", scalar #atz, join(", ", #atz));
All tz names [349] = Africa/Abidjan, Africa/Accra, Africa/Algiers, Africa/Bissau, Africa/Cairo, Africa/Casablanca, Africa/Ceuta, Africa/El_Aaiun, Africa/Johannesburg, Africa/Khartoum, Africa/Lagos, Africa/Maputo, Africa/Monrovia, Africa/Nairobi, Africa/Ndjamena, Africa/Tripoli, Africa/Tunis, Africa/Windhoek, America/Adak, America/Anchorage, America/Araguaina, America/Argentina/Buenos_Aires, America/Argentina/Catamarca, America/Argentina/Cordoba, America/Argentina/Jujuy, America/Argentina/La_Rioja, America/Argentina/Mendoza, America/Argentina/Rio_Gallegos, America/Argentina/Salta, America/Argentina/San_Juan, America/Argentina/San_Luis, America/Argentina/Tucuman, America/Argentina/Ushuaia, America/Asuncion, America/Atikokan, America/Bahia, America/Bahia_Banderas, America/Barbados, America/Belem, America/Belize, America/Blanc-Sablon, America/Boa_Vista, America/Bogota, America/Boise, America/Cambridge_Bay, America/Campo_Grande, America/Cancun, America/Caracas, America/Cayenne, America/Chicago, America/Chihuahua, America/Costa_Rica, America/Creston, America/Cuiaba, America/Curacao, America/Danmarkshavn, America/Dawson, America/Dawson_Creek, America/Denver, America/Detroit, America/Edmonton, America/Eirunepe, America/El_Salvador, America/Fortaleza, America/Glace_Bay, America/Godthab, America/Goose_Bay, America/Grand_Turk, America/Guatemala, America/Guayaquil, America/Guyana, America/Halifax, America/Havana, America/Hermosillo, America/Indiana/Indianapolis, America/Indiana/Knox, America/Indiana/Marengo, America/Indiana/Petersburg, America/Indiana/Tell_City, America/Indiana/Vevay, America/Indiana/Vincennes, America/Indiana/Winamac, America/Inuvik, America/Iqaluit, America/Jamaica, America/Juneau, America/Kentucky/Louisville, America/Kentucky/Monticello, America/La_Paz, America/Lima, America/Los_Angeles, America/Maceio, America/Managua, America/Manaus, America/Martinique, America/Matamoros, America/Mazatlan, America/Menominee, America/Merida, America/Metlakatla, America/Mexico_City, America/Miquelon, America/Moncton, America/Monterrey, America/Montevideo, America/Montreal, America/Nassau, America/New_York, America/Nipigon, America/Nome, America/Noronha, America/North_Dakota/Beulah, America/North_Dakota/Center, America/North_Dakota/New_Salem, America/Ojinaga, America/Panama, America/Pangnirtung, America/Paramaribo, America/Phoenix, America/Port-au-Prince, America/Port_of_Spain, America/Porto_Velho, America/Puerto_Rico, America/Rainy_River, America/Rankin_Inlet, America/Recife, America/Regina, America/Resolute, America/Rio_Branco, America/Santa_Isabel, America/Santarem, America/Santiago, America/Santo_Domingo, America/Sao_Paulo, America/Scoresbysund, America/Sitka, America/St_Johns, America/Swift_Current, America/Tegucigalpa, America/Thule, America/Thunder_Bay, America/Tijuana, America/Toronto, America/Vancouver, America/Whitehorse, America/Winnipeg, America/Yakutat, America/Yellowknife, Antarctica/Casey, Antarctica/Davis, Antarctica/DumontDUrville, Antarctica/Macquarie, Antarctica/Mawson, Antarctica/Palmer, Antarctica/Rothera, Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok, Asia/Almaty, Asia/Amman, Asia/Anadyr, Asia/Aqtau, Asia/Aqtobe, Asia/Ashgabat, Asia/Baghdad, Asia/Baku, Asia/Bangkok, Asia/Beirut, Asia/Bishkek, Asia/Brunei, Asia/Chita, Asia/Choibalsan, Asia/Colombo, Asia/Damascus, Asia/Dhaka, Asia/Dili, Asia/Dubai, Asia/Dushanbe, Asia/Gaza, Asia/Hebron, Asia/Ho_Chi_Minh, Asia/Hong_Kong, Asia/Hovd, Asia/Irkutsk, Asia/Jakarta, Asia/Jayapura, Asia/Jerusalem, Asia/Kabul, Asia/Kamchatka, Asia/Karachi, Asia/Kathmandu, Asia/Khandyga, Asia/Kolkata, Asia/Krasnoyarsk, Asia/Kuala_Lumpur, Asia/Kuching, Asia/Macau, Asia/Magadan, Asia/Makassar, Asia/Manila, Asia/Nicosia, Asia/Novokuznetsk, Asia/Novosibirsk, Asia/Omsk, Asia/Oral, Asia/Pontianak, Asia/Pyongyang, Asia/Qatar, Asia/Qyzylorda, Asia/Rangoon, Asia/Riyadh, Asia/Sakhalin, Asia/Samarkand, Asia/Seoul, Asia/Shanghai, Asia/Singapore, Asia/Srednekolymsk, Asia/Taipei, Asia/Tashkent, Asia/Tbilisi, Asia/Tehran, Asia/Thimphu, Asia/Tokyo, Asia/Ulaanbaatar, Asia/Urumqi, Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg, Asia/Yerevan, Atlantic/Azores, Atlantic/Bermuda, Atlantic/Canary, Atlantic/Cape_Verde, Atlantic/Faroe, Atlantic/Madeira, Atlantic/Reykjavik, Atlantic/South_Georgia, Atlantic/Stanley, Australia/Adelaide, Australia/Brisbane, Australia/Broken_Hill, Australia/Currie, Australia/Darwin, Australia/Eucla, Australia/Hobart, Australia/Lindeman, Australia/Lord_Howe, Australia/Melbourne, Australia/Perth, Australia/Sydney, CET, CST6CDT, EET, EST, EST5EDT, Europe/Amsterdam, Europe/Andorra, Europe/Athens, Europe/Belgrade, Europe/Berlin, Europe/Brussels, Europe/Bucharest, Europe/Budapest, Europe/Chisinau, Europe/Copenhagen, Europe/Dublin, Europe/Gibraltar, Europe/Helsinki, Europe/Istanbul, Europe/Kaliningrad, Europe/Kiev, Europe/Lisbon, Europe/London, Europe/Luxembourg, Europe/Madrid, Europe/Malta, Europe/Minsk, Europe/Monaco, Europe/Moscow, Europe/Oslo, Europe/Paris, Europe/Prague, Europe/Riga, Europe/Rome, Europe/Samara, Europe/Simferopol, Europe/Sofia, Europe/Stockholm, Europe/Tallinn, Europe/Tirane, Europe/Uzhgorod, Europe/Vienna, Europe/Vilnius, Europe/Volgograd, Europe/Warsaw, Europe/Zaporozhye, Europe/Zurich, HST, Indian/Chagos, Indian/Christmas, Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Maldives, Indian/Mauritius, Indian/Reunion, MET, MST, MST7MDT, PST8PDT, Pacific/Apia, Pacific/Auckland, Pacific/Bougainville, Pacific/Chatham, Pacific/Chuuk, Pacific/Easter, Pacific/Efate, Pacific/Enderbury, Pacific/Fakaofo, Pacific/Fiji, Pacific/Funafuti, Pacific/Galapagos, Pacific/Gambier, Pacific/Guadalcanal, Pacific/Guam, Pacific/Honolulu, Pacific/Kiritimati, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro, Pacific/Marquesas, Pacific/Nauru, Pacific/Niue, Pacific/Norfolk, Pacific/Noumea, Pacific/Pago_Pago, Pacific/Palau, Pacific/Pitcairn, Pacific/Pohnpei, Pacific/Port_Moresby, Pacific/Rarotonga, Pacific/Tahiti, Pacific/Tarawa, Pacific/Tongatapu, Pacific/Wake, Pacific/Wallis, UTC, WET