I have an NSString that gets assigned a string value. How do I take this NSString and insert #"-thumbnail" between the file's name and its extension?
In other words, how do I go from:
NSString *fileName = #"myFile.png";
to:
NSString *thumbnailName = [NSString someMagicFunction...]
NSLog(#"%#", thumbnailName); // Should Output "myFile-thumbnail.png"
The NSString additions for path components can come in handy, specifically: pathExtension and stringByDeletingPathExtension
Edit: see also: stringByAppendingPathExtension: (as pointed out by Dave DeLong)
NSString * ext = [fileName pathExtension];
NSString * baseName = [fileName stringByDeletingPathExtension];
NSString * thumbBase = [baseName stringByAppendingString:#"-thumbnail"];
NSString * thumbnailName = [thumbBase stringByAppendingPathExtension:ext];
If you really want that magicFunction to exist, you can add a category method to NSString like so:
#interface NSString (MoreMagic)
- (NSString *)stringByAddingFileSuffix:(NSString *)suffix;
#end
#implementation NSString (MoreMagic)
- (NSString *)stringByAddingFileSuffix:(NSString *)suffix
{
NSString * extension = [self pathExtension];
NSString * baseName = [self stringByDeletingPathExtension];
NSString * thumbBase = [baseName stringByAppendingString:suffix];
return [thumbBase stringByAppendingPathExtension:extension];
}
#end
To be used as follows:
NSString * thumbnailName = [fileName stringByAddingFileSuffix:#"-thumbnail"];
If you are certain of your filenames, you could also simply do:
[NSString stringByReplacingOccurrencesOfString:#"." withString:#"-thumbnail."]
But the path handling stuff is cleaner (doesn't care how many "." you have in the name) and good to know about for trickier cases.
We've got an opensource category for just that: -[NSString ks_stringWithPathSuffix:]
Related
I have an iPhone application in which i am creating an array in the didfinishlaunch in the appdelegate. Like this:
for(int i=1;i<53;i++)
{
NSString *namestring=[NSString stringWithString:#"avatar"];
NSString *string = [NSString stringWithFormat:#"%d",i];
NSString *pngstring=[NSString stringWithString:#".png"];
string = [string stringByAppendingString:pngstring];
namestring = [namestring stringByAppendingString:string];
NSLog(#"%#",namestring);
[avtararray addObject:namestring];
}
working fine.and everywhere i am doing the avatar job with my avatararray in the appdelegate.But in one case when i pop back to the previous view and try to load the string from the array again
NSString *avatarstringt=[[appDelegate.avtararray objectAtIndex:i]description];here it is crashing with a an error
-[CFString description]: message sent to deallocated instance..
when doing the profile job i know that the leak is in the above loop in the appendingstring code.Can anybody help me to remove this?
First of all, Never do this
NSString *string = [NSString stringWithFormat:#"%d",i];
NSString *pngstring=[NSString stringWithString:#".png"];
string = [string stringByAppendingString:pngstring];
The following statements, are redundant
NSString *namestring=[NSString stringWithString:#"avatar"];
NSString *pngstring=[NSString stringWithString:#".png"];
and should be written as:
NSString *namestring=#"avatar";
NSString *pngstring=#".png";
You can use as :
NSString *namestring=#"avatar";
NSString *numberString = [NSString stringWithFormat:#"%d",i];
NSString *pngstring=#"png";
namestring = [namestring stringByAppendingFormat:#"%#.%#",numberString,pngstring];
Even the shortest of code :
for(NSInteger i=1;i<5;i++){
NSString *namestring = [NSString stringWithFormat:#"avatar%#.png",#(i)];
NSLog(#"%#",namestring);
}
As suggested by rmaddy: you can use i as integer, no need of converting it into nsnumber
NSString *namestring = [NSString stringWithFormat:#"avatar%d.png",i];
Ok, say I have the string "hello my name is donald"
Now, I want to remove everything from "hello" to "is"
The thing is, "my name" could be anything, it could also be "his son"
So basically, simply doing stringByReplacingOccurrencesOfString won't work.
(I do have RegexLite)
How would I do this?
Use like below it will help you
NSString *hello = #"his is name is isName";
NSRange rangeSpace = [hello rangeOfString:#" "
options:NSBackwardsSearch];
NSRange isRange = [hello rangeOfString:#"is"
options:NSBackwardsSearch
range:NSMakeRange(0, rangeSpace.location)];
NSString *finalResult = [NSString stringWithFormat:#"%# %#",[hello substringToIndex:[hello rangeOfString:#" "].location],[hello substringFromIndex:isRange.location]];
NSLog(#"finalResult----%#",finalResult);
The following NSString Category may help you. It works good for me but not created by me. Thanks for the author.
NSString+Whitespace.h
#import <Foundation/Foundation.h>
#interface NSString (Whitespace)
- (NSString *)stringByCompressingWhitespaceTo:(NSString *)seperator;
#end
NSString+Whitespace.m
#
import "NSString+Whitespace.h"
#implementation NSString (Whitespace)
- (NSString *)stringByCompressingWhitespaceTo:(NSString *)seperator
{
//NSArray *comps = [self componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSArray *comps = [self componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
NSMutableArray *nonemptyComps = [[NSMutableArray alloc] init];
// only copy non-empty entries
for (NSString *oneComp in comps)
{
if (![oneComp isEqualToString:#""])
{
[nonemptyComps addObject:oneComp];
}
}
return [nonemptyComps componentsJoinedByString:seperator]; // already marked as autoreleased
}
#end
If you always know your string will begin with 'hello my name is ', then that is 17 characters, including the final space, so if you
NSString * hello = "hello my name is Donald Trump";
NSString * finalNameOnly = [hello substringFromIndex:17];
Hi Im really having a hard time saving in my NSDocumentDirectory.Im using AGImagePickerby the way. Yes I was able to save this in NSDocumentDirectory. But how to save them uniquely ( in terms of their own then converting their names into oneSlotImages) or save them with their unique IDs then load them back. Sorry Im kinda new to this UIImagePickerControllerMediaURL thing., I think that would be my solution to my other problem for not overlaping them when saving. How to save this using their unique ID, or UIImagePickerControllerMediaURL.
for (int i = 0; i < info.count; i++) {
NSLog(#"%#", [info objectAtIndex:i]);
NSArray *paths = NSSearchPathForDirectoriesInDomains( NSDocumentDirectory, NSUserDomainMask ,YES );
NSString *documentsDir = [paths objectAtIndex:0];
NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"oneSlotImages%d.png", i]];
ALAssetRepresentation *rep = [[info objectAtIndex: i] defaultRepresentation];
UIImage *image = [UIImage imageWithCGImage:[rep fullResolutionImage]];
//----resize the images
image = [self imageByScalingAndCroppingForSize:image toSize:CGSizeMake(256,256*image.size.height/image.size.width)];
NSData *imageData = UIImagePNGRepresentation(image);
[imageData writeToFile:savedImagePath atomically:YES];
Thanks for the help. Much Appreciated.
You could always keep a list of used names and do something like this
int i = 1;
while([listOfUsedNames containsObject:nextAvailableTile]) {
nextAvailableTitle = [kDefaultImageName stringByAppendingFormat:#" %d", i];
i++;
}
// found an unused name
The URL for each image is unique right? So we can make use of this. Convert the URL into MD5 string (which form a unique identifier for each image). And save with that name (like "MD5string.png").
Why can't we use this?
Hope this helps you.
For converting to MD5, please create a file named NSString+MD5.h and put the code
#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonDigest.h>
#interface NSString(MD5)
- (NSString *)MD5;
#end
in it.
Then in the NSString+MD5.m,
#import "NSString+MD5.h"
#implementation NSString(MD5)
- (NSString*)MD5
{
const char *ptr = [self UTF8String];
unsigned char md5Buffer[CC_MD5_DIGEST_LENGTH];
CC_MD5(ptr, strlen(ptr), md5Buffer);
NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
[output appendFormat:#"%02x",md5Buffer[i]];
return output;
}
#end
Import the NSString+MD5.h class where ever you want to use the MD5 function with normal NSString object.
In you code if you have the UIImagePickerControllerMediaURL string, since it is unique for every file you can convert in to MD5 String like
NSString *imgURL = [NSString stringWithString: UIImagePickerControllerMediaURL];
NSString *MD5String = [imgURL MD5];
NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.png", MD5String]];
Use that path to save your image file.
On Loading,
Convert the UIImagePickerControllerMediaURL into MD5 and check in the Documents directory for the file
// In this the UIImagePickerControllerMediaURL is the URL of media file to load
NSString *imgURL = [NSString stringWithString: UIImagePickerControllerMediaURL];
NSString *MD5String = [imgURL MD5];
NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:#"%#.png", MD5String]];
Then do the checking with the fileExistsAtPath method of NSFileManager and if exists then load the file from the path. Thats it.
Note: For this you want to keep the UIImagePickerControllerMediaURL of the images you saved in documents directory locally somewhere in your app (In DB or NSUserDefaults) for make use of then at the time of loading.
Try this:
NSMutableString *imageName = [[[NSMutableString alloc] initWithCapacity:0] autorelease];
CFUUIDRef theUUID = CFUUIDCreate(kCFAllocatorDefault);
if (theUUID) {
[imageName appendString:NSMakeCollectable(CFUUIDCreateString(kCFAllocatorDefault, theUUID))];
CFRelease(theUUID);
}
[imageName appendString:#".png"];
Hi all i want extract the last part from string which is a four digit number '03276' i:e http://www.abc.com/news/read/welcome-new-gig/03276
how can i do that.
You can also use
NSString *sub = [#"http://www.abc.com/news/read/welcome-new-gig/03276" lastPathComponent];
If you know how many characters you need, you can do something like this:
NSString *string = #"http://www.abc.com/news/read/welcome-new-gig/03276";
NSString *subString = [string substringFromIndex:[string length] - 5];
If you just know that it's the part after the last slash, you can do this:
NSString *string = #"http://www.abc.com/news/read/welcome-new-gig/03276";
NSString *subString = [[string componentsSeparatedByString:#"/"] lastObject];
Since *nix uses the same path separators as URL's this will be valid as well.
[#"http://www.abc.com/news/read/welcome-new-gig/03276" lastPathComponent]
If you know the length of the number, and it's not gonna change, it can be as easy as:
NSString *result = [string substringFromIndex:[string length] - 4];
If the last part of the string is always the same length (5 characters) you could use this method to extract the last part:
- (NSString *)substringFromIndex:(NSUInteger)anIndex
Use the length of the string to determine the start index.
Something like this:
NSString *inputStr = #"http://www.abc.com/news/read/welcome-new-gig/03276";
NSString *newStr = [inputStr substringFromIndex:[inputStr length]-5];
NSLog(#"These are the last five characters of the string: %#", newStr);
(Code not tested)
NSString *str = #"http://www.abc.com/news/read/welcome-new-gig/03276";
NSArray *arr = [str componentSeparatedBy:#"gig/"];
NSString *strSubStringDigNum = [arr objectAtIndex:1];
strSubStringDigNum will have the value 03276
Try this:
NSString *myUrl = #"http://www.abc.com/news/read/welcome-new-gig/03276";
NSString *number = [[myUrl componentsSeparatedByString:#"/"] objectAtIndex: 5];
Trying to append const char *str to a NSSting *:
In .h
#interface SomeViewController : UIViewController
{
NSString *consoleText;
}
#property (nonatomic, retain) NSString *consoleText;
#end
In .mm
#synthesize consoleText;
The following is OK:
const char *str = "abc";
self.consoleText = [NSString stringWithFormat: #"%#%#", self.consoleText, [NSString stringWithUTF8String:str]];
but the following failed:
self.consoleText = [self.consoleText stringByAppendingString:[NSString stringWithUTF8String:str]];
Why stringByAppendingString fails but stringWithFormat works? Thanks!
In two of the operations you are doing different things one is appending existing string and another you are setting a new string
To append string there should be a string object
self.consoleText = [self.consoleText stringByAppendingString:[NSString stringWithUTF8String:str]];
As per understanding self.consoleText ---> nil so it will not appending string.
so do something like
if(self.consoleText)
{
self.consoleText = [self.consoleText stringByAppendingString:[NSString stringWithUTF8String:str]];
}else
{
self.consoleText = [NSString stringWithUTF8String:str];
}
NSString *original = #"Thinking";
const char *str = "...";
NSString *other = [NSString stringWithCString:str encoding:NSASCIIStringEncoding];
original = [original stringByAppendingString:other];
NSLog(#"original: %#", original); // original: Thinking...