iOS动态保留小数点后位数

最近在做分时K线的项目，牵涉到刻度轴的时候，产品要求根据昨日的收盘价进行小数位的保留，不足补零。

debug效果

debu代码

    NSLog(@"%@",[ViewController notRounding:@(0.1246) afterPoint:1]);
    NSLog(@"%@",[ViewController notRounding:@(0.1246) afterPoint:2]);
    NSLog(@"%@",[ViewController notRounding:@(0.1246) afterPoint:3]);
    NSLog(@"%@",[ViewController notRounding:@(0.1246) afterPoint:4]);
    NSLog(@"%@",[ViewController notRounding:@(0.1246) afterPoint:5]);

核心代码逻辑

+ (NSString *)notRounding:(id)price
               afterPoint:(NSInteger)position {
    //生成format格式
    NSString *format = [NSString stringWithFormat:@"%%.%ldf",(long)position];
    CGFloat value = 0.;
    //string 和 number 兼容
    if ([price respondsToSelector:@selector(doubleValue)]) {
        value = [price doubleValue];
    }
    NSString *number = [NSString stringWithFormat:format,value];
    return number;
}