Objective C How to detect one or multiple spaces in a NSString

问题

I have seen one answer for my task, but I couldnt find it now. I want to detect whether a string has empty word and contains at least "" or " " (two spaces" or more multiple spaces, OR not. If not, I would add this to Nsmutablearray. If yes with empty or at least one space, I would like it not to be written to mutablearray.

How to solve this?

EDIT 12 October 2011:

Guys, thank you.

Again I am sorry that I was unclear about my wish. I wanted to check if a string is empty or contains whitespaces without any character. I have posted my answer below.

回答1:

Im not sure whether it is the most performant way of doing it but you could split your array and see whether the length is greater than 1:

if ([string componentsSeparatedByString:@" "].count > 1)

http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html

回答2:

    if( bookmarked.length == 0 )
    {
        NSLog (@"not allowed: empty");

    } 
    else if ([[bookmarked stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length] == 0)        
    { 
        NSLog (@"not allowed: whitespace(s)");
    }

    else 
    {
        [bookmarklist addObject:bookmarked];
    }

回答3:

Depends if you're looking for ANY whitespace or just spaces. For spaces you can use:

if( [string length] == 0 ||
    !NSEqualRanges( [string rangeofString:@" "],
                    NSMakeRange(NSNotFound, 0) ) )
{
    // either the string is empty or we found a space
} else {
    // we didn't find a space and the string is at least of length 1
}

If any whitespace, use the whitespace character set:

if( [string length] == 0 ||
    !NSEqualRanges( [string rangeOfCharacterFromSet:
                     [NSCharacterSet whitespaceCharacterSet]],
                    NSMakeRange(NSNotFound, 0) ) )
{
    // either the string is empty or we found a space
} else {
    // we didn't find a space and the string is at least of length 1
}

Replace whitespaceCharacterSet with whitespaceAndNewlineCharacterSet if you like.

回答4:

Look at the documentation for NSString.

Specifically, look under the section Finding Characters and Substrings for the method you want, probably you want to use – rangeOfString:options:range: multiple times.

Also, look under the section Replacing Substrings for the method you want, probably you want to use – stringByReplacingOccurrencesOfString:withString:options:range:

回答5:

Take a look at the NSRegularExpression class and coding examples.

回答6:

NSString *myString = @"ABC defa   jh";
int spaceCount = [[myString componentsSeparatedByString:@" "] count] - 1;

if (!spaceCount) {
    // Zero spaces, Do Something
} else if (spaceCount <= 2) {
    // 1-2 spaces add this to NSMutableArray (although the wording about what you wanted to do in each case is confusing, so adjust for your needs)
} else {
    // 3+ spaces, Do Not add this to NSMutableArray (adjust for your needs)
}

来源：https://stackoverflow.com/questions/7707320/objective-c-how-to-detect-one-or-multiple-spaces-in-a-nsstring

标签

objective-c

nsstring