在NSString中的句号或问号前修剪空格

Question

If I have a string like "How are you doing ?" or "I am fine ."

how can I get -

"How are you doing?" or "I am fine."

I want to remove whitespace between the last word and "?" or "."

Answer 1

You could use stringByReplacingOccurrencesOfString . And with the use of the NSRegularExpressionSearch option, you could handle all of the different permutations in a single statement:

NSString *result = [string stringByReplacingOccurrencesOfString:@"\\s+([.?])"
                                                     withString:@"$1"
                                                        options:NSRegularExpressionSearch
                                                          range:NSMakeRange(0, [string length])];

Regular expressions can be cryptic (see NSRegularExpression documentation for more information), but this says "find any strings that consists of one or more whitespace characters (space, tab, newline, etc.) followed by a full stop (period) or question mark and replace with just the full stop or question mark you found." You can refine that as needed, but hopefully this illustrates the concept.

Answer 2

I don't see an immediate way to do that. I would just search the range of any character that you want - like in your case question marks and dots - and check if there's a space before it, and in case remove the space. This is an example:

NSString* str= @"How are you doing ?";
NSRange range= [str rangeOfCharacterFromSet: [NSCharacterSet characterSetWithCharactersInString: @".?"]];
if(range.location!= NSNotFound)
{
    if(range.location>0 && [str characterAtIndex: range.location-1]==' ')
    {
        str= [str stringByReplacingCharactersInRange: NSMakeRange(range.location-1, 1) withString: @""];
    }
}