判断NSString是否为数字,以及转换为数字

from: http://blog.sina.com.cn/s/blog_a343f32b010134tm.html

当NSString为纯数字的时候可以用下面的方法：

 

//判断是否为整形：

- (BOOL)isPureInt:(NSString*)string{

    NSScanner* scan = [NSScanner scannerWithString:string]; 

    intval; 

    return[scanscanInt:&val] && [scanisAtEnd];

}

 

//判断是否为浮点形：

- (BOOL)isPureFloat:(NSString*)string{

    NSScanner* scan = [NSScanner scannerWithString:string]; 

    floatval; 

    return[scanscanFloat:&val] && [scanisAtEnd];

}

 

更复杂点的Question:

I have an NSString like so:

@"200hello" or   @"0 something" 

What I would like to be able to do is take the first occuring number in the NSString and convert it into an int.

So that @"200hello" would become int = 200.

and @"0 something" would become int = 0.

Answer1（数字和字符排序不规则）:

intvalue;  BOOL success=[[NSScannerscannerWithString:@"1000safkaj"]scanInteger:&value]; 

If the number is not always at the beginning:

NSCharacterSet* nonDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet]; 
int value = [[@"adfsdg1000safkaj" stringByTrimmingCharactersInSet:nonDigits] intValue]; 

Answer2（数字总是在字符前）:

If the int value is always at the beginning of the string, you can simply use intValue.

NSString*string=@"123hello";  

int myInt = [string intValue];