I'm trying to parse HTML code and extra some data from with using regular expressions. The website that provides the data has no API and I want to show this data in an iOS app build using Swift. The HTML looks like this:
$(document).ready(function() {
var years = ['2020','2021','2022'];
var currentView = 0;
var amounts = [1269.2358,1456.557,1546.8768];
var balances = [3484626,3683646,3683070];
rest of the html code
What I'm trying to extract is the years, amounts and balances.
So I would like to have an array with the year in in [2020,2021,2022] same for amount and balances. In this example there are 3 years, but it could be more or less. I'm able to extra all the numbers but then I'm unable to link them to the years or amounts or balances. See this example: https://regex101.com/r/WMwUji/1, using this pattern (\d|\[(\d|,\s*)*])
Any help would be really appreciated.
Firstly I think there are some errors in your expression. To capture the whole number you have to use \d+ (which matches 1 or more consecutive numbers e.g. 2020). If you need to include . as a separator the expression then would look like \d+\.\d+.
In addition using non-capturing group, (?:) and non-greedy matches .*? the regular-expression that gives the desired result for years is
(?:year.*?|',')(\d+)
This can also be modified for the amount field which would look like this:
(?:amounts.*?|,)(\d+\.\d+)
You can try it here: https://regex101.com/r/QLcFQN/1
Edited: in the previous Version my proposed regex was non functional and only captured the last match.
You can continue with this regex:
^var (years \= (?'year'.*)|balances \= (?'balances'.*)|amounts \= (?'amounts'.*));$
It searches for lines with either years, balances or amount entries and names the matches acordingly. It matches the whole string within the brackets.
Related
Context
I am designing a code that runs a bunch of calculations, and outputs figures. At the end of the code, I want to save everything in a nice way, so my take on this is to go to a user specified Output directory, create a new folder and then run the save process.
Question(s)
My question is twofold:
I want my folder name to be unique. I was thinking about getting the current date and time and creating a unique name from this and the input filename. This works but it generates folder names that are a bit cryptic. Is there some good practice / convention I have not heard of to do that?
When I get the datetime string (tn = datestr(now);), it looks like that:
tn =
'07-Jul-2022 09:28:54'
To convert it to a nice filename, i replace the '-',' ' and ':' characters by underscores and append it to a shorter version of the input filename chosen by the user. I do that using strrep:
tn = strrep(tn,'-','_');
tn = strrep(tn,' ','_');
tn = strrep(tn,':','_');
This is fine but it bugs me to have to use 3 lines of code to do so. Is there a nice one liner to do that? More generally, is there a way to look for every non letter or number character in a string and replace it with a given character? I bet that's what regexp is there for but frankly I can't quite get a hold on how regexps work.
Your point (1) is opinion based so you might get a variety of answers, but I think a common convention is to at least start the name with a reverse-order date string so that sorting alphabetically is the same as sorting chronologically (i.e. yymmddHHMMSS).
To answer your main question directly, you can use the built-in makeValidName utility which is designed for making valid variable names, but works for making similarly "plain" file names.
str = '07-Jul-2022 09:28:54';
str = matlab.lang.makeValidName(str)
% str = 'x07_Jul_202209_28_54'
Because a valid variable can't start with a number, it prefixes an x - you could avoid this by manually prefixing something more descriptive first.
This option is a bit more simple than working out the regex, although that would be another option which isn't too nasty here using regexprep and replacing non-alphanumeric chars with an underscore:
str = regexprep( str, '\W', '_' ); % \W (capital W) matches all non-alphanumeric chars
% str = '07_Jul_2022_09_28_54'
To answer indirectly with a different approach, a nice trick with datestr which gets around this issue and addresses point (1) in one hit is to use the following syntax:
str = datestr( now(), 30 );
% str = '20220707T094214'
The 30 input (from the docs) gives you an ISO standardised string to the nearest second in reverse-order:
'yyyymmddTHHMMSS' (ISO 8601)
(note the T in the middle isn't a placeholder for some time measurement, it remains a literal letter T to split the date and time parts).
I normally use your folder naming approach with a meaningful prefix, replacing ':' by something else:
folder_name = ['results_' strrep(datestr(now), ':', '.')];
As for your second question, you can use isstrprop:
folder_name(~isstrprop(folder_name, 'alphanum')) = '_';
Or if you want more control on the allowed characters you can use good old ismember:
folder_name(~ismember(folder_name, ['0':'9' 'a':'z' 'A':'Z'])) = '_';
I am trying to create a regular expression to determine if a string contains a number for an SQL statement. If the value is numeric, then I want to add 1 to it. If the number is not numeric, I want to return a 1. More or less. Here is the SQL:
SELECT
field,
CASE
WHEN regexp_like(field, '^ *\d*\.?\d* *$') THEN dec(field) + 1
ELSE 1
END nextnumber
FROM mytable
This actually works, and returns something like this:
INVALID 1
00000 1
00001E 1
00379 380
00013 14
99904 99905
But to push the envelope of understanding, what if I wanted to cover negative numbers, or those with a positive sign. The sign would have to immediately precede or follow the number, but not both, and I would not want to allow white space between the sign and the number.
I came up with a conditional expression with a capture group to capture the sign on the front of the number to determine if a sign was allowed on the end, but it seems a little awkward to handle given I don't really need a yes-pattern.
Here is the modified regex: ^ ([+-]?)*\d*\.?\d*(?(1) *|[+-]? *)$
This works at regex101.com, but in order for it to work I need to have something before the pipe, so I have to duplicate the next pattern in both the yes-pattern and the no-pattern.
All that background for this question: How can I avoid that duplication?
EDIT: DB2 for i uses International Components for Unicode to provide regular expression processing. It turns out that this library does not support conditionals like PRCE, so I changed the tags on this question. The answer given by Wiktor Stribiżew provides a working alternative to the conditional by using a negative lookahead.
You do not have to duplicate the end pattern, just move it outside the conditional:
^ *([+-])?\d*\.?\d*(?(1)|[+-]?) *$
See the regex demo. So, the yes-part is empty, and the no-part has an optional pattern.
You may also solve it with a mere negative lookahead:
^ *([+-](?!.*[-+]))?\d*\.?\d*[+-]? *$
See another regex demo. Here, ([+-](?!.*[-+]))? matches (optionally) a + or - that are not followed with any 0+ char followed with another + or -.
I have a DB2 v7r3 SQL SELECT statement with three instances of REGEXP_SUBSTR(), all with the same regex pattern string, each of which extract one of three groups.
I'd like to change the first SUBSTR to REGEXP_REPLACE() to do a conditional replacement if there's no match, to insert a default value similarly to the ELSE section of a CASE...END. But I can't make it work. I could easily use a CASE, but it seems more compact & efficient to use RegEx.
For example, I have descriptions of food containers sizes, in various states of completeness:
12X125
6X350
1X1500
1500ML
1000
The last two don't have the 'nnX' part at the beginning, in which case '1X' is assumed and needs to be inserted.
This is my current working pattern string:
^(?:(\d{1,3})(?:X))?((?:\d{1,4})(?:\.\d{1,3})?)(L|ML|PK|Z|)$
The groups returned are: quantity, size, and unit.
But only the first group needs the conditional replacement:
(?:(\d{1,3})(?:X))?
This RexEgg webpage describes the (?=...) operator, and it seems to be what I need, but I'm not sure. It's in the list of operators for my version of DB2, but I can't make it work. Frankly, it's a bit deeper than my regex knowledge, and I can't even make it work in my favorite online regex tester, Regex101.
So...does anyone have any idea or suggestions..? Thanks.
Try this (replace "digits not followed by X_or_digit"):
with t(s) as (values
'12X125'
, '6X350'
, '1X1500'
, '1500'
, '1125'
)
select regexp_replace(s, '^([\d]+(?![X\d]))', '1X\1')
from t;
How to use matlab regexprep , for multiple expression and replacements?
file='http:xxx/sys/tags/Rel/total';
I want to replace 'sys' with sys1 and 'total' with 'total1'. For a single expression a replacement it works like this:
strrep(file,'sys', 'sys1')
and want to have like
strrep(file,'sys','sys1','total','total1') .
I know this doesn't work for strrep
Why not just issue the command twice?
file = 'http:xxx/sys/tags/Rel/total';
file = strrep(file,'sys','sys1')
strrep(file,'total','total1')
To solve it you need substitute functionality with regex, try to find in matlab's regexes something similar to this in php:
$string = 'http:xxx/sys/tags/Rel/total';
preg_replace('/http:(.*?)\//', 'http:${1}1/', $string);
${1} means 1st match group, that is what in parenthesis, (.*?).
http:(.*?)\/ - match pattern
http:${1}1/ - replace pattern with second 1 as you wish to add (first 1 is a group number)
http:xxx/sys/tags/Rel/total - input string
The secret is that whatever is matched by (.*?) (whether xxx or yyyy or 1234) will be inserted instead of ${1} in replace pattern, and then replace instead of old stuff into the input string. Welcome to see more examples on substitute functionality in php.
As documented in the help page for regexprep, you can specify pairs of patterns and replacements like this:
file='http:xxx/sys/tags/Rel/total';
regexprep(file, {'sys' 'total'}, {'sys1' 'total1'})
ans =
http:xxx/sys1/tags/Rel/total1
It is even possible to use tokens, should you be able to define a match pattern for everything you want to replace:
regexprep(file, '/([st][yo][^/$]*)', '/$11')
ans =
http:xxx/sys1/tags/Rel/total1
However, care must be taken with the first approach under certain circumstances, because MATLAB replaces the pairs one after another. That is to say if, say, the first pattern matches a string and replaces it with something that is subsequently matched by a later pattern, then that will also be replaced by the later replacement, even though it might not have matched the later pattern in the original string.
Example:
regexprep('This\is{not}LaTeX.', {'\\' '([{}])'}, {'\\textbackslash{}' '\\$1'})
ans =
This\textbackslash\{\}is\{not\}LaTeX.
=> This\{}is{not}LaTeX.
and
regexprep('This\is{not}LaTeX.', {'([{}])' '\\'}, {'\\$1' '\\textbackslash{}'})
ans =
This\textbackslash{}is\textbackslash{}{not\textbackslash{}}LaTeX.
=> This\is\not\LaTeX.
Both results are unintended, and there seems to be no way around this with consecutive replacements instead of simultaneous ones.
I want to parse an html webpage (Specifically a Google Search Results Page)
Looking for the specific counter string
"About *many results"
where *many can range from 0 to 999,999,999,999 results
grep("About [0-9] results",file)
I can't figure out how to incorporate the range of numbers (including commas) into the regular expression. Can anyone clarify? I've looked for similar questions posted, but their codes do not work for this task.
I'm guessing introduce some kind of wildcard "." but I don't think I'm using it correctly
The structure I had in mind was
Any#Times { { Any#Times( [0-9] ) },}
Solved own question...
didn't have to be fancy at all
"About .* results"
works fine
Depending on the content of the page then your .* works, but could get a very long and incorrect string.
If you want to make sure that you get only numbers, try:
"About ([0-9]+|[0-9]{1,3}(,[0-9]{3})*) results"
I've tested it with grep -E and it'll give you ungrouped numbers:
About 10000000 results
as well as grouped numbers using British/English conventions:
About 100,000 results
but not non-numbers:
About a bajillion results
or badly grouped numbers:
About 100,0 results