1.定义一个字符串a, 截取a 的某一个部分，复制给b, b必须是int型 NSString *a = @"1.2.30"; int b= [[a substringWithRange:NSMakeRange(4,2)] intValue]; NSLog(@"a:%@ n",a ); NSLog(@"b:%d",b ); 解析如下：substringWithRange: 专门截取字符串的一块肉 NSMakeRange(4,2) 从第4个字符开始截取，长度为2个字符，（字符串都是从第0个字符开始数的哦～！） b = [a intValue]; 将 a 转换为 整数型 b = [a floatValue]; 将 a 转换为 小数型 b = [a boolValue]; 将 a 转换为 布尔型（true / false） b = [a integerValue]; 将 a 转换为 整数型 b = [a longLongValue]; 将 a 转换为 长整型 2.字符串截取到第n位 （substringToIndex: n）(第n 位不算再内) - (void)viewDidLoad { NSString *a = @"i like long dress"; NSString *b = [a substringToIndex:4]; NSLog(@"n b: %@",b); } 3.字符串从第n 位开始截取,直到最后 （substringFromIndex:n）（包括第 n 位） - (void)viewDidLoad { NSString *a = @"i like long dress"; NSString*b = [a substringFromIndex:4]; NSLog(@"n b: %@",b); } 4.从某一个字符串中的一个字符串开始截取 - (void)viewDidLoad { NSString *a ="/pubic/evdaily.nsf/vwtrymaindocid/8E88469482579180035442A/$file/测试帐号及信息22.docx"; NSRange range = [arangeOfString:@"$file/"];//获取$file/的位置 NSString *b = [a substringFromIndex:range.location + range.length];//开始截取 NSLog(@"n b: %@",b); }
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]; int val; return[scan scanInt:&val] && [scan isAtEnd]; } //判断是否为浮点形： - (BOOL)isPureFloat:(NSString*)string{ NSScanner* scan = [NSScanner scannerWithString:string]; float val; return[scan scanFloat:&val] && [scan isAtEnd]; } 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];
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