CODEWITHSUNDEEP
objective-cxcodensstringsubstring
user1415780
user1415780

Reputation: 1153

removing all the string content before a certain string in an NSString

I am trying to see if there is a short way of doing the following:

let s say I have the following NSString:
@"123456 copy cat";

I need to remove everything before "copy" and the length of the text before it is variable (depends on the user input)

I know that I can probably do an endless for loop to check the substring but I hope that there is a faster way

Upvotes: 0

Views: 5221

Answers (2)

Extra Savoir-Faire
Extra Savoir-Faire

Reputation: 6036

NSString *string = @"123456 copy cat";
NSRange range = [string rangeOfString:@"copy"];
NSString *newString = [string substringFromIndex:range.location];

That's the simple answer. The problem is that your user may enter the word 'copy', and then what? Even if you get the range this way:

NSRange range = [string rangeOfString:@"copy cat"];

there's still a chance your user may enter that phrase as well. By the time you put in additional checks, it's no longer a "short way."

EDIT

Don't overlook Chuck's excellent observation in the comments for using:

-[NSString rangeOfString:options:]

Upvotes: 12

puzzle
puzzle

Reputation: 6131

To remove part of a string you will either have to create a new string containing the part that you want to keep, or create a mutable copy of your string and modify that.

To create a new string containing the part starting with "copy":

NSString *input;
NSString *output;
NSRange copyRange;

input = @"123456 copy cat";
copyRange = [input rangeOfString:@"copy"];
output = [input substringFromIndex:copyRange.location];

To create a mutable string and remove the part up to "copy":

NSString *input;
NSMutableString *output;
NSRange copyRange;

input = @"123456 copy cat";
output = [input mutableCopy];
copyRange = [output rangeOfString:@"copy"];
[output replaceCharactersInRange:NSMakeRange(0, copyRange.location) withString:@""];
[output autorelease]; // depending on what you want to do

Please also see the comments in the other answer about using rangeOfString:withOptions: with NSBackwardsSearch in case the user input also contains the word "input".

Upvotes: 2

Related Questions