产生随机订单号

#pragma mark - 产生随机订单号
- (NSString *)generateTradeNO {
    static int kNumber = 16; // 订单号长度
    
    NSString *sourceStr = @"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // 订单号组成字符集
    NSMutableString *resultStr = [[NSMutableString alloc] init];
    srand((unsigned)time(0));
    for (int i = 0; i < kNumber; i++)
    {
        unsigned index = rand() % [sourceStr length];
        NSString *oneStr = [sourceStr substringWithRange:NSMakeRange(index, 1)];
        [resultStr appendString:oneStr];
    }
    return resultStr;
}

时间戳字符串

- (NSString *)stringDate:(NSDate *)date {
    NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyyMMddHHmmss"];
    NSString *today = [dateFormatter stringFromDate:date];
    return today;
}

随机颜色

+ (UIColor *)random {
    CGFloat hue = (arc4random() % 256 / 256.0);  //  0.0 to 1.0
    CGFloat saturation = (arc4random() % 128 / 256.0) + 0.5;  //  0.5 to 1.0, away from white
    CGFloat brightness = (arc4random() % 128 / 256.0) + 0.5;  //  0.5 to 1.0, away from black
    return [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:1];
}

验证有效邮箱

- (BOOL)isValidateEmail:(NSString *)email {
    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailTest evaluateWithObject:email];
}

容量转换为易读的字符串(Size to GB)

    function humanFileSize(bytes, si) {
        var thresh = si ? 1000 : 1024;
        if(bytes < thresh) return bytes + ' B';
        var units = si ? ['kB','MB','GB','TB','PB','EB','ZB','YB'] : ['KiB','MiB','GiB','TiB','PiB','EiB','ZiB','YiB'];
        var u = -1;
        do {
            bytes /= thresh;
            ++u;
        } while(bytes >= thresh);
        return bytes.toFixed(1)+' '+units[u];
    }