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Closed 11 years ago.
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Remove double quotes from NSString
I have a string with double double quotes "" that I need to replace with single double quotes ".
I've tried the following but I still end up with double double quotes
NSString *str = #"This is a \"\"99\"\" string";
[str stringByReplacingOccurrencesOfString: #"\"\"" withString: #"\""];
Initially the string is: This is a ""99"" string
After the stringByReplacingOccurrencesOfString: This is a ""99"" string.
What am I doing wrong?
It looks like you are expecting str to contain your modified string. Instead, you should be looking at the return value of the stringByReplacingOccurrencesOfString:withString: function:
NSString *str = #"This is a \"\"99\"\" string";
NSString *result =[str stringByReplacingOccurrencesOfString: #"\"\"" withString: #"\""];
NSLog(#"before: %# after: %#", str, result);
NSString objects are immutable. If you want str to be mutable, look into NSMutableString: documentation link
The method you are calling doesn't change the original NSString. It returns a new NSString with the replacements you've asked for.
Save the new string and use that.
Related
This question already has answers here:
Remove Characters and Everything After from String
(2 answers)
Closed 8 years ago.
I can't seem to find the answer to this anywhere. I can do it in c but objective c is difficult.
I want to cut the end of a string after a certain character
so user#example.com will become user (cut at '#')
How do I do this?
This will give you the first chunk of text that comes before your special character.
NSString *separatorString = #"#";
NSString *myString = #"user#example.com";
NSString *myNewString = [myString componentsSeparatedByString:separatorString].firstObject;
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html#//apple_ref/occ/instm/NSString/componentsSeparatedByString:
You can use a combination of substringToIndex: and rangeOfString: methods, like this:
NSString *str = #"user#example.com";
NSRange pos = [str rangeOfString:#"#"];
if (pos.location != NSNotFound) {
NSString *prefix = [str substringToIndex:pos.location];
}
Notes:
You need to check the location against NSNotFound to ensure that the position is valid.
substringToIndex: excludes the index itself, so the # character would not be included.
NSString *string = #"HELLO";
For some reason, XCode won't auto-complete methods like remove characters or append etc... If that's the case, how can I, say, remove certain characters from my string? Say I want to remove all the L's.
NSString doesn't respond to those methods. NSMutableString does, but you've declared an immutable string variable and assigned to it a string literal. Since an Objective-C #"string literal" is always immutable (an instance of NSString but not NSMutableString), there's no way those messages can be sent to the object you're using.
If you want a mutable string, try:
NSMutableString *mutableString = [[#"HELLO" mutableCopy] autorelease];
That's an immutable string literal.
Here is a great post explaining it in further details:
What's the difference between a string constant and a string literal?
As for your question on how would you change it and remove the Ls:
NSString *hello = #"HELLO";
NSString *subString = [hello stringByReplacingOccurrencesOfString:#"L" withString:#""];
NSLog(#"subString: %#", subString);
That outputs "HEO"
Either that or you can create an NSMutableString by creating a copy of the mutable string like Jonathan mentioned. In both examples, you're copying it into a non-literal string.
Hoping somebody can help me out - I would like to replace a certain character in a string and am wondering what is the best way to do this?
I know the location of the character, so for example, if I want to change the 3rd character in a string from A to B - how would I code that?
If it is always the same character you can use:
stringByReplacingOccurrencesOfString:withString:
If it is the same string in the same location you can use:
stringByReplacingOccurrencesOfString:withString:options:range:
If is just a specific location you can use:
stringByReplacingCharactersInRange:withString:
Documentation here:
https://developer.apple.com/documentation/foundation/nsstring
So for example:
NSString *someText = #"Goat";
NSRange range = NSMakeRange(0,1);
NSString *newText = [someText stringByReplacingCharactersInRange:range withString:#"B"];
newText would equal "Boat"
NSString *str = #"123*abc";
str = [str stringByReplacingOccurrencesOfString:#"*" withString:#""];
//str now 123abc
Here is the code:
[aString stringByReplacingCharactersInRange:NSMakeRange(3,1) withString:#"B"];
Use the replaceCharactersInRange: withString: message on a NSMutableString object.
I have an NSString and fail to apply the following statement:
NSString *myString = #"some text";
[myString stringByAppendingFormat:#"some text = %d", 3];
no log or error, the string just doesn't get changed. I already tried with NSString (as documented) and NSMutableString.
any clues most welcome.
I would suggest correcting to (documentation):
NSString *myString = #"some text";
myString = [myString stringByAppendingFormat:#" = %d", 3];
From the docs:
Returns a string made by appending to the receiver a string constructed from a given format string and the following arguments.
It's working, you're just ignoring the return value, which is the string with the appended format. (See the docs.) You can't modify an NSString — to modify an NSMutableString, use -appendFormat: instead.
Of course, in your toy example, you could shorten it to this:
NSString *myString = [NSString stringWithFormat:#"some text = %d", 3];
However, it's likely that you need to append a format string to an existing string created elsewhere. In that case, and particularly if you're appending multiple parts, it's good to think about and balance the pros and cons of using a mutable string or several immutable, autoreleased strings.
Creating strings with #"" always results in immutable strings. If you want to create a new NSMutableString do it as following.
NSMutableString *myString = [NSMutableString stringWithString:#"some text"];
[myString appendFormat:#"some text = %d", 3];
I had a similar warning message while appending a localized string. This is how I resolved it
NSString *msgBody = [msgBody stringByAppendingFormat:#"%#",NSLocalizedString(#"LOCALSTRINGMSG",#"Message Body")];
I have a fairly simple question concerning NSString however it doesn't seem to do what I want.
this is what i have
NSString *title = [NSString stringWithformat: character.name, #"is the character"];
This is a line in my parser takes the charactername and inserts in into a plist , however it doesn't insert the #"is the character" is there something I'm doing wrong?
Your code is wrong. It should be :
NSString *title
= [NSString stringWithformat:#"%# is the character", character.name];
assuming that character.name is another NSString.
Read the Formatting String Objects paragraph of the String Programming Guide for Cocoa to learn everything about formatting strings.
stringWithFormat takes a format string as the first argument so, assuming character.name is the name of your character, you need:
NSString *title = [NSString stringWithformat: #"%s is the character",
character.name];
What you have is the character name as the format string so, if it's #"Bob" then Bob is what you'll get. If it was "#Bob %s", that would work but would probably stuff up somewhere else that you display just the character name :-)
Note that you should use "%s" for a C string, I think "%#" is the correct format specifier if character.name is an NSString itself.