NSScanner简单用法

NSScanner可用于检测字符串中是否包含指定字符串、整形、浮点型、特殊字符， 

    NSString *str = @"abcd12.3<4b5bv99-9v6.7f=ff00";
    NSScanner *scanner = [NSScanner scannerWithString:str];
    
    NSString *temp = @"";
    NSInteger index = 0;
    NSCharacterSet *charSet = [NSCharacterSet characterSetWithCharactersInString:@"=-<"];
    
    //设置扫描忽略的字符集
    [scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"="]];
    
    //从位置0开始扫描，直到扫描结束，可获得匹配成功的字符
    while (![scanner isAtEnd]) {
        if ([scanner scanCharactersFromSet:charSet intoString:&temp]) {
            NSLog(@"%@", temp);
        }

        index++;
        [scanner setScanLocation:index];
    }
    
    //匹配到字符集中的任何一个字符，立即停止扫描，返回第一个匹配字符之前的字符串
    if ([scanner scanUpToCharactersFromSet:charSet intoString:&temp]) {
        NSLog(@"%@", temp);
    }
    
    //匹配字符串中的数字
    while (![scanner isAtEnd]) {
        int result = 0;
        if ([scanner scanInt:&result]) {
            NSLog(@"%zd", result);
            NSNumber *number = [NSNumber numberWithInt:result];
            index = index + number.stringValue.length;
            [scanner setScanLocation:index];
        }else {
            index++;
            [scanner setScanLocation:index];
        }
    }
    
    //匹配字符串中的浮点数
    while (![scanner isAtEnd]) {
        float result = 0;
        if ([scanner scanFloat:&result]) {
            NSLog(@"%f", result);
            NSNumber *number = [NSNumber numberWithFloat:result];
            index = index + number.stringValue.length;
            [scanner setScanLocation:index];
        }else {
            index++;
            [scanner setScanLocation:index];
        }
    }
    
    //匹配到字符串“b”后立即停止
    BOOL flag = [scanner scanUpToString:@"b" intoString:&temp];