iOS 让数字保持两位数格式

NSLog(@"%02ld",2);
NSLog(@"%0.2f",0.2656);
NSLog(@"%0.2f",0.2646);

注意的是%0.2f 是会对数字进行一个四舍五入

    2021-01-20 14:57:28.506 App[4010:98217] 02
    2021-01-20 14:57:28.507 App[4010:98217] 0.27
    2021-01-20 14:57:28.507 App[4010:98217] 0.26