Column 从元素为map的切片中，找到所有map指定的key对应的value值，并返回切片.

Implode 将任意类型数组，按照分割符，转成字符串.

Merge any number of slices into a slice.

Pad Add padding of given size to fill the slice, with the specified value val.

A new slice is generated by randomly taking n elements from the original slice.