objective-c - 如何将 NSString 从 CamelCase 转换为 TitleCase，将“playerName”转换为“Player Name”？

Question

我正在寻找将字符串从驼峰格式转换为标题大小写格式的最简单方法。

如何将“playerName”更改为“Player Name”？

score 21 · Accepted Answer

NSString *str = @"playerName";
NSMutableString *str2 = [NSMutableString string];

for (NSInteger i=0; i<str.length; i++){
    NSString *ch = [str substringWithRange:NSMakeRange(i, 1)];
    if ([ch rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
        [str2 appendString:@" "];
    }
    [str2 appendString:ch];
}
NSLog(@"%@", str2.capitalizedString);

score 15 · Accepted Answer

这是一个更简单的 Swift 版本。我已将其放入扩展程序中

extension String {

    func stringFromCamelCase() -> String {
        var string = self
        string = string.stringByReplacingOccurrencesOfString("([a-z])([A-Z])", withString: "$1 $2", options: NSStringCompareOptions.RegularExpressionSearch, range: Range<String.Index>(start: string.startIndex, end: string.endIndex))
        string.replaceRange(startIndex...startIndex, with: String(self[startIndex]).capitalizedString)
        return string
    }

}

用法：

var str = "helloWorld"
str = str.stringFromCamelCase()

score 12 · Accepted Answer

尝试使用正则表达式替换

NSString *modified = [input stringByReplacingOccurrencesOfString:@"([a-z])([A-Z])"
                                                      withString:@"$1 $2"
                                                         options:NSRegularExpressionSearch
                                                           range:NSMakeRange(0, input.length)];

score 5 · Accepted Answer

稍微短一点，使用 NSCharacterSet：

__block NSString *str = @"myVerySpecialPlayerName" ;

// split at uppercase letters
NSArray *splitString = [str componentsSeparatedByCharactersInSet:
     [NSCharacterSet uppercaseLetterCharacterSet]] ;

// get the uppercase letters
NSArray *upperCaseLetters = [str componentsSeparatedByCharactersInSet:
     [[NSCharacterSet uppercaseLetterCharacterSet] invertedSet]] ;

// join with two spaces
str = [splitString componentsJoinedByString:@"  "] ;
__block NSInteger offset = 0 ;

// replace each second space with the missing uppercase letter
[upperCaseLetters enumerateObjectsUsingBlock:^(NSString *character, NSUInteger idx, BOOL *stop) {
    if( [character length] > 0 ) {
        str = [str stringByReplacingCharactersInRange:NSMakeRange(idx+offset+1, 1) withString:character] ;
        offset += 2 ;
    }
}] ;

// & capitalize the first one
str = [str capitalizedString] ;

NSLog(@"%@", str) ; // "My Very Special Player Name"

score 3 · Accepted Answer

尝试更符合 unicode

extension String {
    func camelCaseToTitleCase() -> String {
        return unicodeScalars.map(replaceCaptialsWithSpacePlusCapital).joined().capitalized
    }
    private func replaceCaptialsWithSpacePlusCapital(unichar: UnicodeScalar) -> String {
        if CharacterSet.uppercaseLetters.contains(unichar) {
            return " \(unichar)"
        }
        return "\(unichar)"
    }
}

score 2 · Accepted Answer

我认为您可以使用一些正则表达式来解决这个问题。看看这个类似的问题：iPhone dev: Replace uppercase characters in NSString with space and downcase

score 2 · Accepted Answer

虽然有点长，但是这个类对于 NSString 应该可以解决问题。它通过了我所有的测试：

- (NSString *)splitOnCapital
{
  // Make a index of uppercase characters
  NSRange upcaseRange = NSMakeRange('A', 26);
  NSIndexSet *upcaseSet = [NSIndexSet indexSetWithIndexesInRange:upcaseRange];

  // Split our camecase word
  NSMutableString *result = [NSMutableString string];
  NSMutableString *oneWord = [NSMutableString string];
  for (int i = 0; i < self.length; i++) {
    char oneChar = [self characterAtIndex:i];
    if ([upcaseSet containsIndex:oneChar]) {
      // Found a uppercase char, now save previous word
      if (result.length == 0) {
        // First word, no space in beginning
        [result appendFormat:@"%@", [oneWord capitalizedString]];
      }else {
        [result appendFormat:@" %@", oneWord];
      }

      // Clear previous word for new word
      oneWord = [NSMutableString string];
    }

    [oneWord appendFormat:@"%c", oneChar];
  }

  // Add last word
  if (oneWord.length > 0) {
    [result appendFormat:@" %@", oneWord];
  }

  return result;
}

score 2 · Accepted Answer

我有一个类似的问题，这里的答案帮助我创建了一个解决方案。我有一个数组，其中包含我想在 UITableView 中显示的标签列表，每行一个标签。

我的问题是我从 SOAP 操作返回的 XML 中解析了这些标签，但我不知道字符串的格式。

首先，我将 webstersx answer 实现到一个方法中。这很棒，但是其中一些标签以大写字母开头，而一些以驼峰式开头（例如，一些字符串 whereexampleLabel和其他 where ExampleLabel。所以这意味着以大写字母开头的那些在字符串前面插入了一个空格。

我通过使用 NSString 修剪字符串开头和结尾的空格来克服这个问题stringByTrimmingCharactersInSet。

下一个问题是使用的任何缩写，例如“ID”或“PNR Status”，其中显示为“ID”和“PNR Status”作为大写字母，并且非常正确地被选中并在其前面插入一个空格.

我通过在我的新方法中实现类似于 emdog4 的答案的正则表达式克服了这个问题。

这是我完成的解决方案：

- (NSString *)formatLabel:(NSString *)label
{
    NSMutableString *str2 = [NSMutableString string];

    for (NSInteger i=0; i<label.length; i++){
        NSString *ch = [label substringWithRange:NSMakeRange(i, 1)];
        if ([ch rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
            [str2 appendString:@" "];
        }
        [str2 appendString:ch];
    }
    NSString * formattedString = [str2 stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]].capitalizedString;

    formattedString = [formattedString stringByReplacingOccurrencesOfString:@"([A-Z]) (?![A-Z][a-z])" withString:@"$1" options:NSRegularExpressionSearch range:NSMakeRange(0, formattedString.length)];

    return formattedString;
}

然后我简单地调用这样的东西，例如，这将返回我格式化的字符串：

NSString * formattedLabel = [self formatLabel:@"PNRStatus"];
NSLog(@"Formatted Label: %@", formattedLabel);

将输出：

2013-10-10 10:44:39.888 测试项目[28296:a0b] 格式化标签：PNR 状态

score 2 · Accepted Answer

如果有人需要 Swift 版本：

func camelCaseToTitleCase(s: NSString) -> String {
    var newString = ""
    if s.length > 0 {
        newString = s.substringToIndex(1).uppercaseString
        for i in 1..<s.length {
            let char = s.characterAtIndex(i)
            if NSCharacterSet.uppercaseLetterCharacterSet().characterIsMember(char) {
                newString += " "
            }
            newString += s.substringWithRange(NSRange(location: i, length: 1))
        }
    }
    return newString
}

score 1 · Accepted Answer

虽然技术上更短，但效率更低

NSString *challengeString = @"playerName";
NSMutableString *rStr = [NSMutableString stringWithString:challengeString];

while ([rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]].location != NSNotFound) {
    [rStr replaceCharactersInRange:[rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]] withString:[[NSString stringWithFormat:@" %@", [rStr substringWithRange:[rStr rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]]]] lowercaseString]];
}

NSLog(@"%@", rStr.capitalizedString);

score 1 · Accepted Answer

不确定这比 websterx 短得多，但我发现使用 characterIsMember 更容易阅读和理解。如果字符串以大写字母开头，还添加了长度检查以修复空格。

NSString *str = @"PlayerNameHowAboutALongerString";
NSMutableString *str2 = [NSMutableString string];

for (NSInteger i=0; i<str.length; i++){
    unichar ch = [str characterAtIndex:i];
    if ( [[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:ch]) {
        if (str2.length > 0 ) {
            [str2 appendString:@" "];
        }
    }
    [str2 appendString:[NSString stringWithCharacters:&ch length:1]];
}
NSLog(@"--%@--", str2.capitalizedString);

score 1 · Accepted Answer

接受的答案对我不起作用，因为它没有将第一个字母大写，如果第一个字母已经大写，它会在开头添加一个无关的空格。这是我的改进版本：

- (NSString *)titleFromCamelCaseString:(NSString *)input
{
    NSMutableString *output = [NSMutableString string];
    [output appendString:[[input substringToIndex:1] uppercaseString]];
    for (NSUInteger i = 1; i < [input length]; i++)
    {
        unichar character = [input characterAtIndex:i];
        if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:character])
        {
            [output appendString:@" "];
        }
        [output appendFormat:@"%C", character];
    }
    return output;
}

score 0 · Accepted Answer

这是 Swift 代码（webstersx 的目标 c 代码），谢谢！

var str: NSMutableString = "iLoveSwiftCode"

        var str2: NSMutableString = NSMutableString()

        for var i:NSInteger = 0 ; i < str.length ; i++ {

            var ch:NSString = str.substringWithRange(NSMakeRange(i, 1))
            if(ch .rangeOfCharacterFromSet(NSCharacterSet.uppercaseLetterCharacterSet()).location != NSNotFound) {
            str2 .appendString(" ")
            }
            str2 .appendString(ch)
        }
        println("\(str2.capitalizedString)")

    }

score 0 · Accepted Answer

NSString *input = @"playerName";
NSString *modified = [input stringByReplacingOccurrencesOfString:@"(?<!^)[A-Z]" withString:@" $0" options:NSRegularExpressionSearch range:NSMakeRange(0, input.length)].capitalizedString;

score 0 · Accepted Answer

Swift 2.2 下的另一种解决方案

extension String {
    var stringFromCamelCase:String {
        return (self as NSString).replacingOccurrences(
            of: "([a-z])([A-Z])",
            with: "$1 $2",
            options: CompareOptions.regularExpressionSearch,
            range: NSMakeRange(0, self.characters.count)
            ).uppercaseFirst
    }

    var uppercaseFirst: String {
        return String(characters.prefix(1)).uppercased() + String(characters.dropFirst()).lowercased()
    }
}

score -8 · Accepted Answer

-8

尝试使用：

string.Split()

然后使用大写字母作为标记

于 2011-01-04T03:52:53.467 回答

objective-c - 如何将 NSString 从 CamelCase 转换为 TitleCase，将“playerName”转换为“Player Name”？

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