Question

我遇到了一些代码问题。我把它缩小到这个问题：首先，reverseString和2都是NSMutableStrings _input1和_input2都是NSStrings，我试图添加零到最小的字符串，但它没有正常工作，这就是我得到的。 reverseString为@"123"，reverseString2为@"34567"。

 //they get initialized back into the original strings
_input1=reversedString;
_input2=reversedString2;
//appends 0 to the shortest value
while ([_input1 length]>[_input2 length]){
    _input2=[_input2 stringByAppendingString:@"0"];
    _length=[_input1 length];
}
while ([_input1 length]<[_input2 length]){
    _input1=[_input1 stringByAppendingString:@"0"];
    _length=[_input2 length];
}

//converts the string to an NSArray
for (int i=0; i <([_input1 length]); i++) {
    NSString *TempStr = [_input1 substringWithRange:NSMakeRange(i, 1)];
    [one addObject:[TempStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}


for (int i=0; i <([_input2 length]); i++) {
    NSString *TempStr2 = [_input2 substringWithRange:NSMakeRange(i, 1)];
    [two addObject:[TempStr2 stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}

现在我注意到，当它经历这个循环时，最小的一个_input1被设置为@""，而不是在末尾添加零。顺便说一下，这是一个班级。

这也是我收到的错误：

objc [2291]：方法缓存已损坏。这可能是对无效对象的消息，也可能是其他地方的内存错误。   objc [2291]：接收器0x100300830，SEL 0x7fff8a689779，isa 0x7fff727b8bd0，缓存0x7fff727b8be0，桶0x7fff89b9b09c，掩码0x1，占用0x0，换行桶0x7fff89b9b09c
  objc [2291]：接收器0字节，桶0字节
  objc [2291]：选择器＆＃39;长度＆＃39;
  （lldb）

Answer 1

试试以下代码

if([_input1 length] > [_input2 length])
{
   for (int i = 0 ; i < [_input1 length] - [_input2 length] ; i ++)
     _input2 = [_input2 stringByAppendingString:@"0"];
}
else
{
   for (int i = 0 ; i < [_input2 length] - [_input1 length] ; i ++)
     _input1 = [_input1 stringByAppendingString:@"0"];
}

Answer 2

试试这样： -

   NSString *input1=@"123";
   NSString * input2=@"34567";
    NSMutableArray *one=[NSMutableArray array];
        NSMutableArray *two=[NSMutableArray array];

    //appends 0 to the shortest value
    while ([input1 length]>[input2 length]){
        input2=[input2 stringByAppendingString:@"0"];
        //length=[input1 length];
    }
    while ([input1 length]<[input2 length]){
        input1=[input1 stringByAppendingString:@"0"];
       // length=[input2 length];
    }

    for (int i=0; i <([input1 length]); i++) {
        NSString *TempStr = [input1 substringWithRange:NSMakeRange(i, 1)];
        [one addObject:[TempStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

    }

            NSLog(@"%ld",[one count]);
    for (int i=0; i <([input2 length]); i++) {
        NSString *TempStr2 = [input2 substringWithRange:NSMakeRange(i, 1)];
        [two addObject:[TempStr2 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

    }
                    NSLog(@"%ld",[two count]);

Answer 3

您的要求不是很清楚，但这是您提议的代码的更清晰版本

NSString *string1 = @"foo";
NSString *string2 = @"foobar";

// Compute the desired length
NSUInteger length = MAX(string1.length, string2.length);
// We will pad using this string
NSString *paddingString = @"0";

// Pad both strings to the same length
string1 = [string1 stringByPaddingToLength:length withString:paddingString startingAtIndex:0];
string2 = [string2 stringByPaddingToLength:length withString:paddingString startingAtIndex:0];

// Build two arrays containing the characters, percent escaped
NSMutableArray *charactersArray1 = [NSMutableArray arrayWithCapacity:string1.length];
NSMutableArray *charactersArray2 = [NSMutableArray arrayWithCapacity:string2.length];
for (NSInteger i = 0; i < string1.length; i++) {
    [charactersArray1 addObject:[[string1 substringWithRange:(NSRange){ i, 1 }] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    [charactersArray2 addObject:[[string2 substringWithRange:(NSRange){ i, 1 }] stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}
NSLog(@"String 1: %@\nString 2: %@", charactersArray1, charactersArray2);

结果将是

字符串1：[f，o，o，0,0,0]
字符串2：[f，o，o，b，a，r]

Answer 4

我想出了我的问题，_input1和_input2是坏指针，我不得不修复它，抱歉所有的困惑，最后我的代码工作了！

在NSString的末尾附加零？

4 个答案: