How to capitalize the first word of the sentence in Objective-C?

问题

I've already found how to capitalize all words of the sentence, but not the first word only.

NSString *txt =@"hi my friends!"
[txt capitalizedString];

I don't want to change to lower case and capitalize the first char. I'd like to capitalize the first word only without change the others.

回答1:

Here is another go at it:

NSString *txt = @"hi my friends!";
txt = [txt stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[txt substringToIndex:1] uppercaseString]];

For Swift language:

txt.replaceRange(txt.startIndex...txt.startIndex, with: String(txt[txt.startIndex]).capitalizedString)

回答2:

The accepted answer is wrong. First, it is not correct to treat the units of NSString as "characters" in the sense that a user expects. There are surrogate pairs. There are combining sequences. Splitting those will produce incorrect results. Second, it is not necessarily the case that uppercasing the first character produces the same result as capitalizing a word containing that character. Languages can be context-sensitive.

The correct way to do this is to get the frameworks to identify words (and possibly sentences) in the locale-appropriate manner. And also to capitalize in the locale-appropriate manner.

[aMutableString enumerateSubstringsInRange:NSMakeRange(0, [aMutableString length])
                                   options:NSStringEnumerationByWords | NSStringEnumerationLocalized
                                usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
    [aMutableString replaceCharactersInRange:substringRange
                                  withString:[substring capitalizedStringWithLocale:[NSLocale currentLocale]]];
    *stop = YES;
}];

It's possible that the first word of a string is not the same as the first word of the first sentence of a string. To identify the first (or each) sentence of the string and then capitalize the first word of that (or those), then surround the above in an outer invocation of -enumerateSubstringsInRange:options:usingBlock: using NSStringEnumerationBySentences | NSStringEnumerationLocalized. In the inner invocation, pass the substringRange provided by the outer invocation as the range argument.

回答3:

Use

- (NSArray *)componentsSeparatedByCharactersInSet:(NSCharacterSet *)separator

and capitalize the first object in the array and then use

- (NSString *)componentsJoinedByString:(NSString *)separator

to join them back

回答4:

pString = [pString
           stringByReplacingCharactersInRange:NSMakeRange(0,1)
           withString:[[pString substringToIndex:1] capitalizedString]];

回答5:

you can user with regular expression i have done it's works for me simple you can paste below code +(NSString*)CaptializeFirstCharacterOfSentence:(NSString*)sentence{

NSMutableString *firstCharacter = [sentence mutableCopy];
NSString *pattern = @"(^|\\.|\\?|\\!)\\s*(\\p{Letter})";
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:pattern options:0 error:NULL];
[regex enumerateMatchesInString:sentence options:0 range:NSMakeRange(0, [sentence length]) usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
    //NSLog(@"%@", result);
    NSRange r = [result rangeAtIndex:2];
    [firstCharacter replaceCharactersInRange:r withString:[[sentence substringWithRange:r] uppercaseString]];
}];
NSLog(@"%@", firstCharacter);
return firstCharacter;

} //Call this method NsString *resultSentence = [UserClass CaptializeFirstCharacterOfSentence:yourTexthere];

回答6:

For the sake of having options, I'd suggest:

NSString *myString = [NSString stringWithFormat:@"this is a string..."];

char *tmpStr = calloc([myString length] + 1,sizeof(char));

[myString getCString:tmpStr maxLength:[myString length] + 1 encoding:NSUTF8StringEncoding];

int sIndex = 0;

/* skip non-alpha characters at beginning of string */
while (!isalpha(tmpStr[sIndex])) {
    sIndex++;
}

toupper(tmpStr[sIndex]);

myString = [NSString stringWithCString:tmpStr encoding:NSUTF8StringEncoding];

I'm at work and don't have my Mac to test this on, but if I remember correctly, you couldn't use [myString cStringUsingEncoding:NSUTF8StringEncoding] because it returns a const char *.

回答7:

In swift you can do it as followed by using this extension:

extension String {
    func ucfirst() -> String {
        return (self as NSString).stringByReplacingCharactersInRange(NSMakeRange(0, 1), withString: (self as NSString).substringToIndex(1).uppercaseString)
    }    
}

calling your string like this:

var ucfirstString:String = "test".ucfirst()

回答8:

An alternative solution in Swift:

var str = "hello"

if count(str) > 0 {
    str.splice(String(str.removeAtIndex(str.startIndex)).uppercaseString, atIndex: str.startIndex)
}

回答9:

I know the question asks specifically for an Objective C answer, however here is a solution for Swift 2.0:

let txt = "hi my friends!"
var sentencecaseString = ""

for (index, character) in txt.characters.enumerate() {
    if 0 == index {
        sentencecaseString += String(character).uppercaseString
    } else {
        sentencecaseString.append(character)
    }
}

Or as an extension:

func sentencecaseString() -> String {
    var sentencecaseString = ""
    for (index, character) in self.characters.enumerate() {
        if 0 == index {
            sentencecaseString += String(character).uppercaseString
        } else {
            sentencecaseString.append(character)
        }
    }
    return sentencecaseString
}

来源：https://stackoverflow.com/questions/2432452/how-to-capitalize-the-first-word-of-the-sentence-in-objective-c