Question

我有一个像@"abcdefghijklmnopqrstuvwxyzA"这样的字符串。如您所见，A即将结束。如何找到第一个大写字母并拆分字符串：

NSString *lower = @"abcdefghijklmnopqrstuvwxyz";
NSString *upper = @"A";

开头的字符串是静态的，因此大写字母可以是任何字母。这个扫描仪有帮助吗？

NSString *String = titleLabelLatestNews.text;

NSScanner *stringScanner = [NSScanner scannerWithString:String];    
NSString *content = [[NSString alloc] init];

while ([stringScanner isAtEnd] == NO) {

    [stringScanner scanUpToString:@"url=\"" intoString:Nil];

    [stringScanner scanUpToString:@"/>" intoString:&content];
}

另一个例子，@"this is all lower case letters I am awesome";应该变成两个字符串，@"this is all lower case letters";和@"I am awesome";

明白了吗？大写字母前的任何内容都会转到字符串，然后转到另一个字符串。

Answer 1

NSScanner会为你做伎俩，是的。您只需创建一个由大写字母组成的NSCharacterSet，然后使用scanUpToCharactersFromSet:intoString:

NSString * s = @"this is all lower case letters I am awesome";
NSScanner * scanner = [NSScanner scannerWithString:s];
NSString * firstPart;
[scanner scanUpToCharactersFromSet:[NSCharacterSet uppercaseLetterCharacterSet]
                        intoString:&firstPart];
NSString * secondPart = [s substringFromIndex:[scanner scanLocation]];

Answer 2

如果您坚持使用NSScanner，请使用scanCharactersFromSet:intoString:，其中NSCharacterSet仅为小写字符。

如果有人关心的话，我个人会做的就是致电rangeOfCharacterFromSet(NSCharacterSet.uppercaseLetterCharacterSet()...)并从那里得到所产生的子串。

Answer 3

更好的解决方案是使用NSString＆＃39; rangeOfCharacterFromSet

 NSString *lowerCaseString=@"";
 NSString *upperCaseString=@"";
 NSString *stringToSplit = titleLabelLatestNews.text;
 NSRange capitalRange=[stringToSplit rangeOfCharacterFromSet:[NSCharacterSet uppercaseLetterCharacterSet]];
 if (capitalRange.location == NSNotFound) {
    lowerCaseString=stringToSplit;
 }
 else if (capitalRange.location ==0 ) {
    upperCaseString=stringToSplit;
 }
 else {
    lowerCaseString=[stringToSplit substringToIndex:capitalRange.location-1];
    upperCaseString=[stringToSplit substringFromIndex:capitalRange.location];
 }

 NSLog(@"lower case string=%@ uppercase=%@",lowerCaseString,upperCaseString);

Answer 4

为了完整性，正则表达式解决方案：

使用NSRegularExpression
如果您只对A-Z感兴趣，那么模式@"([^A-Z]*)([A-Z].*)"将匹配您想要的大写字符（请参阅下面的unicode更改）。细分为两组，(...)，一组用于之前;第一组 - 任何非大写的，[^A-Z]，零次或多次，*;第二组 - 大写字母[A-Z]，后跟任何内容.*。
使用firstMatchInString:options:range:; NSTextCheckingResult将包含两个匹配组的范围。

如果您希望允许使用Unicode无数的大写和标题字母，只需将上面的A-Z更改为\\p{Lu}\\p{Lt}（确保键入双反斜杠，即可将反斜杠传递给NSRegularExpression）。这两个都是Unicode大写字母\\p{Lu}和所有标题大小写字母\\p{Lt}。

HTH

Answer 5

使用componentsSeparatedByCharactersInSet:将一个或多个解决方案投入到混合中，将字符串拆分为多个数组（如果需要，则超过2个）：

// Separate the "sentence" into components separated
// by the characters in the uppercase character set
NSMutableArray *sentenceArray = [[sentence componentsSeparatedByCharactersInSet:[NSCharacterSet uppercaseLetterCharacterSet]] mutableCopy];

// Get the first sentence "segment", i.e. the sentenceArray's
// first object
NSString *segment = [sentenceArray objectAtIndex:0];

// Keep track of the character count with a variable
int characterCount = (int)segment.length;

// Then starting from sentenceArray's index 1, go through
// the rest of sentenceArray's indices
for (int i = 1 ; i < sentenceArray.count ; i ++) {

    // Append that "separator" character to the segment at the
    // current index by accessing the character before the current segment
    segment = [[NSString stringWithFormat:@"%c", [sentence characterAtIndex:characterCount]]stringByAppendingString:[sentenceArray objectAtIndex:i]];

    // Replace the object at the current index with this new segment
    // string
    [sentenceArray replaceObjectAtIndex:i withObject:segment];

     // Increment the character count
    characterCount += segment.length;
}

NSLog(@"%@", sentenceArray);

Answer 6

// Find index of first capital letter
NSInteger index = ^NSInteger{
    for (NSInteger i = 0; i < string.length; ++i) {
        unichar c = [string characterAtIndex:i];
        if ('A' <= c && c <= 'Z') { return i; }
    }

    return string.length; // No capital letter, take the entire string
}();

NSLog(@"lower = %@", [string substringToIndex:index]);
NSLog(@"upper = %@", [string substringFromIndex:index]);

在第一个大写字母处拆分NSString

6 个答案: