If I want to get a value from the NSString @"value:hello World:value", what should I use?
The return value I want is @"hello World".
This question is related to
objective-c
cocoa-touch
nsstring
Option 1:
NSString *haystack = @"value:hello World:value";
NSString *haystackPrefix = @"value:";
NSString *haystackSuffix = @":value";
NSRange needleRange = NSMakeRange(haystackPrefix.length,
haystack.length - haystackPrefix.length - haystackSuffix.length);
NSString *needle = [haystack substringWithRange:needleRange];
NSLog(@"needle: %@", needle); // -> "hello World"
Option 2:
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^value:(.+?):value$" options:0 error:nil];
NSTextCheckingResult *match = [regex firstMatchInString:haystack options:NSAnchoredSearch range:NSMakeRange(0, haystack.length)];
NSRange needleRange = [match rangeAtIndex: 1];
NSString *needle = [haystack substringWithRange:needleRange];
This one might be a bit over the top for your rather trivial case though.
Option 3:
NSString *needle = [haystack componentsSeparatedByString:@":"][1];
This one creates three temporary strings and an array while splitting.
All snippets assume that what's searched for is actually contained in the string.
Here's a simple function that lets you do what you are looking for:
- (NSString *)getSubstring:(NSString *)value betweenString:(NSString *)separator
{
NSRange firstInstance = [value rangeOfString:separator];
NSRange secondInstance = [[value substringFromIndex:firstInstance.location + firstInstance.length] rangeOfString:separator];
NSRange finalRange = NSMakeRange(firstInstance.location + separator.length, secondInstance.location);
return [value substringWithRange:finalRange];
}
Usage:
NSString *myName = [self getSubstring:@"This is my :name:, woo!!" betweenString:@":"];
Here is a little combination of @Regexident Option 1 and @Garett answers, to get a powerful string cutter between a prefix and suffix, with MORE...ANDMORE words on it.
NSString *haystack = @"MOREvalue:hello World:valueANDMORE";
NSString *prefix = @"value:";
NSString *suffix = @":value";
NSRange prefixRange = [haystack rangeOfString:prefix];
NSRange suffixRange = [[haystack substringFromIndex:prefixRange.location+prefixRange.length] rangeOfString:suffix];
NSRange needleRange = NSMakeRange(prefixRange.location+prefix.length, suffixRange.location);
NSString *needle = [haystack substringWithRange:needleRange];
NSLog(@"needle: %@", needle);
Here's a slightly less complicated answer:
NSString *myString = @"abcdefg";
NSString *mySmallerString = [myString substringToIndex:4];
See also substringWithRange and substringFromIndex
Use this also
NSString *ChkStr = [MyString substringWithRange:NSMakeRange(5, 26)];
Note - Your NSMakeRange(start, end) should be NSMakeRange(start, end- start);
Source: Stackoverflow.com