ios - 从 NSString 获取常用字符作为子字符串

Question

我试图在 NSString 中获取重复的字符及其计数。

例如，setupsetpreset 作为输入，它返回 'set' 和计数 3。

让我用另一个例子来解释。

输入 1:
预设

预期输出 1:设置 2

输入 2:
qwertygdgpopgdg

预期输出 2: gdg 2

Answer 1

请参阅下文

NSString *string     = @"This is a test. This is only a test.";
NSCountedSet *countedSet = [NSCountedSet new];

[string enumerateSubstringsInRange:NSMakeRange(0, [string length])
                       options:NSStringEnumerationByWords | NSStringEnumerationLocalized
                    usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop){

                        // This block is called once for each word in the string.
                        [countedSet addObject:substring];

                        // If you want to ignore case, so that "this" and "This" 
                        // are counted the same, use this line instead to convert
                        // each word to lowercase first:
                        // [countedSet addObject:[substring lowercaseString]];
                    }];

NSLog(@"%@", countedSet);

结果:

“这个” - 2
"is" - 2
“a2
“测试” - 2
“只有1个