Pig round down to the nth decimal place

Question

How do you round a float or double down to the nth decimal place in pig. For example

f(3.999999, 1) =  3.9
f(3.42317, 2) = 3.42
f(1.03, 1) = 1.0

I really only need to round to the 1st decimal place but thought i'd leave the question general. I saw the "pig round decimal to two places" question but the answer wasn't explained to the point where i could adapt it to this. Thanks

---

Answer

Turns out math solves this pretty easily. Just do:

FLOOR(column * 10^n) / 10^n

Answer 1

PIG具有ROUND_TO。这将根据所需的小数点进行舍入。

B = FOREACH A GENERATE ROUND_TO(input,num_of_decimal_places);

例：

输入文件：

3.999999
3.42317
1.03

A =以（num：float）的形式加载'file'; B = FOREACH A GENERATE ROUND_TO（num，2）; 转储B;

输出：

(4.0)
(3.42)
(1.03)