concatenate

Merges two lists.

concatenate(xs:list, ys:list) -> list

Description

The concatenate function returns a list containing all elements from the lists xs and ys in order. The expression concatenate(xs, ys) is equivalent to [...xs, ...ys].

If either argument is null, it contributes no elements. For example, concatenate([1], null) returns [1], and concatenate(null, [2]) returns [2].

Examples

Concatenate two lists

from {xs: [1, 2], ys: [3, 4]}
zs = concatenate(xs, ys)

{
  xs: [1, 2],
  ys: [3, 4],
  zs: [1, 2, 3, 4]
}

Concatenate nullable lists

from {xs: null}
left = concatenate([1], xs)
right = concatenate(xs, [2])

{
  xs: null,
  left: [
    1,
  ],
  right: [
    2,
  ],
}

See Also

• fnappend
• fnmerge
• fnprepend
• fnzip
• Shape lists
• Learn idiomatic TQL