Question

我有一个字符串，例如@"012"，我有另一个字符串@"02"。如何在iPhone Objective-C中提取2个字符串的差异。我只需要从第一个字符串中删除第二个字符串中字符的存在。答案是“1”。

Answer 1

更短：

NSString* s1 = @"012";
NSString* s2 = @"02";
NSCharacterSet * set = [NSCharacterSet characterSetWithCharactersInString:s2];
NSString * final = [[s1 componentsSeparatedByCharactersInSet:set] componentsJoinedByString:@""];
NSLog(@"Final: %@", final);

这会保留原始字符串中字符的顺序。

Answer 2

你可以做这样的事情;

NSString *s1 = @"012";
NSString *s2 = @"02";

NSCharacterSet *charactersToRemove;
charactersToRemove = [NSCharacterSet characterSetWithCharactersInString:s2];

NSMutableString *result = [NSMutableString stringWithCapacity:[s1 length]];
for (NSUInteger i = 0; i < [s1 length]; i++) {
    unichar c = [s1 characterAtIndex:i];
    if (![charactersToRemove characterIsMember:c]) {
        [result appendFormat:@"%C", c];
    }
}

// if memory is an issue:
result = [[result copy] autorelease];

免责声明：我在浏览器中输入了此内容，但尚未对此进行测试。

Answer 3

您正在尝试进行设置操作，因此请使用sets。

{
    NSString* s1 = @"012";
    NSString* s2 = @"02";

    NSMutableSet* set1 = [NSMutableSet set];
    NSMutableSet* set2 = [NSMutableSet set];

    for(NSUInteger i = 0; i < [s1 length]; ++i)
    {
        [set1 addObject:[s1 substringWithRange:NSMakeRange(i, 1)]];
    }

    for(NSUInteger i = 0; i < [s2 length]; ++i)
    {
        [set2 addObject:[s2 substringWithRange:NSMakeRange(i, 1)]];
    }


    [set1 minusSet:set2];

    NSLog(@"set1: %@", set1);

    // To get a single NSString back from the set:
    NSMutableString* result = [NSMutableString string];
    for(NSString* piece in set1)
    {
        [result appendString:piece];
    }

    NSLog(@"result: %@", result);
}

Answer 4

我只是使用“componentsSeparatedByString”

NSString *s1 = @"abc"; 
NSString *s2 = @"abcdef";

//s2 - s1
NSString * final = [[s2 componentsSeparatedByString:s1] componentsJoinedByString:@""];

减去2个字符串

4 个答案: