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v/vlib/maps/maps.v

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module maps
// filter filters map entries by the given predicate function
pub fn filter<K, V>(m map[K]V, f fn (K, V) bool) map[K]V {
mut mp := map[K]V{}
for k, v in m {
if f(k, v) {
mp[k] = v
}
}
return mp
}
// to_array maps map entries into one-dimensional array
pub fn to_array<K, V, I>(m map[K]V, f fn (K, V) I) []I {
mut a := []I{cap: m.len}
for k, v in m {
a << f(k, v)
}
return a
}
// flatten maps map entries into arrays and flattens into a one-dimensional array
pub fn flatten<K, V, I>(m map[K]V, f fn (K, V) []I) []I {
mut a := []I{cap: m.len}
for k, v in m {
a << f(k, v)
}
return a
}
// to_map maps map entries into new entries and constructs a new map
pub fn to_map<K, V, X, Y>(m map[K]V, f fn (K, V) (X, Y)) map[X]Y {
mut mp := map[X]Y{}
for k, v in m {
x, y := f(k, v)
mp[x] = y
}
return mp
}
// invert returns a new map, created by swapping key to value and vice versa for each entry.
pub fn invert<K, V>(m map[K]V) map[V]K {
mut mp := map[V]K{}
for k, v in m {
mp[v] = k
}
return mp
}
// from_array maps array into map with index to element per entry
pub fn from_array<T>(a []T) map[int]T {
mut mp := map[int]T{}
for i, e in a {
mp[i] = e
}
return mp
}