Iphone nsstring和nsinteger转换

我有两个数组，第一个数组包含数字，第二个数组使用这些数字作为索引

NSArray *dayOfWeek = [NSArray arrayWithObjects:@"D",@"L",@"M", @"X",@"J",@"V",@"S", nil];

NSArray *arrayDays = [days componentsSeparatedByString:@" "];     

 //arrayDays  2 3 4 5 6 

     NSString *daysPrint;

     for (NSString *theDay in arrayDays) {
         NSLog(@"string %@",theDay);
         NSInteger dayIndex = (NSInteger)theDay;
         NSLog(@"integer %d", dayIndex);
         daysPrint = [NSString stringWithFormat:@"%@ %@", daysPrint, [dayOfWeek objectAtIndex:dayIndex]];

     }

在日志中：

2012-07-02 12:49:27.322 usualBike[1698:f803] string 2
2012-07-02 12:49:27.323 usualBike[1698:f803] integer 109471840

很明显，当我试图获得dayOfWeek[109461840]时，它崩溃了

我怎样才能解决这个问题

先谢谢你

for (NSString *theDay in arrayDays) {
     NSLog(@"string %@",theDay);
     int dayIndex = [theDay intValue];
     NSLog(@"integer %d", dayIndex);
     daysPrint = [NSString stringWithFormat:@"%@ %@", daysPrint, [dayOfWeek objectAtIndex:dayIndex]];

 }

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这可能会帮助您……

您可以使用NSString实例方法，如[theDay intValue]进行整数转换。不需要投你自己

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希望这能有所帮助。

daysPrint将为空。你需要将其赋值为空值，这是崩溃的原因

NSArray *dayOfWeek = [NSArray arrayWithObjects:@"D",@"L",@"M", @"X",@"J",@"V",@"S", nil];

NSArray *arrayDays = [days componentsSeparatedByString:@" "];     

//arrayDays  2 3 4 5 6 

NSString *daysPrint=@"";

for (NSString *theDay in arrayDays) {
    NSLog(@"string %@",theDay);
    NSInteger dayIndex = [theDay intValue];
    NSLog(@"integer %d", dayIndex);
    daysPrint = [NSString stringWithFormat:@"%@ %@", daysPrint, [dayOfWeek objectAtIndex:dayIndex]];

}

使用

相反，请使用此

 for (NSString *theDay in arrayDays) {
    NSLog(@"string %@",theDay);
    NSInteger dayIndex = [theDay intValue];     // change this code
    NSLog(@"integer %d", dayIndex);
    daysPrint = [NSString stringWithFormat:@"%@ %@", daysPrint, [dayOfWeek objectAtIndex:dayIndex]];

}

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NSArray*arrayDays=[days componentsSeparatedByString:@”“]在这个“days”中是一个字符串？使用NSLog打印“days”。要获取“dayIndex”，请使用[Day intValue]。字符串daysPrint将显示为null，并且dayOfWeek没有用于索引dayIndex的元素。如何获取“days”字符串。请添加一些代码。

 for (NSString *theDay in arrayDays) {
    NSLog(@"string %@",theDay);
    NSInteger dayIndex = [theDay intValue];     // change this code
    NSLog(@"integer %d", dayIndex);
    daysPrint = [NSString stringWithFormat:@"%@ %@", daysPrint, [dayOfWeek objectAtIndex:dayIndex]];

}