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arrays: implement python-inspired array zip function and test (#8667)

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nyx-litenite 2021-03-07 04:58:13 -05:00 committed by GitHub
parent 82085b0140
commit a902178fdb
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2 changed files with 60 additions and 0 deletions

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@ -98,6 +98,33 @@ pub fn merge<T>(a []T, b []T) []T {
return m
}
// group n arrays into a single array of arrays with n elements
pub fn group<T>(lists ...[]T) [][]T {
mut length := if lists.len > 0 { lists[0].len } else { 0 }
// calculate length of output by finding shortest input array
for ndx in 1 .. lists.len {
if lists[ndx].len < length {
length = lists[ndx].len
}
}
if length > 0 {
mut arr := [][]T{cap: length}
// append all combined arrays into the resultant array
for ndx in 0 .. length {
mut zipped := []T{cap: lists.len}
// combine each list item for the ndx position into one array
for list_ndx in 0 .. lists.len {
zipped << lists[list_ndx][ndx]
}
arr << zipped
}
return arr
}
return [][]T{}
}
[deprecated]
pub fn shuffle<T>(mut a []T, n int) {
panic('Please use rand.util.shuffle() instead')

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@ -52,3 +52,36 @@ fn test_merge() {
assert merge<int>(a, c) == a
assert merge<int>(d, b) == b
}
fn test_fixed_array_assignment() {
mut a := [2]int{}
a[0] = 111
a[1] = 222
b := a
assert b[0] == a[0]
assert b[1] == a[1]
mut c := [2]int{}
c = a
assert c[0] == a[0]
assert c[1] == a[1]
d := [3]int{init: 333}
for val in d {
assert val == 333
}
e := [3]string{init: 'vlang'}
for val in e {
assert val == 'vlang'
}
}
fn test_group() {
x := [4, 5, 6]
y := [2, 1, 3]
z := group<int>(x, y)
assert z == [[4, 2], [5, 1], [6, 3]]
x2 := [8, 9]
z2 := group<int>(x2, y)
assert z2 == [[8, 2], [9, 1]]
assert group<int>(x, []int{}) == [][]int{}
}