blob: 7d755eced64ddc4c5b7cc2a8afdaedc798816e16 (
plain)
1
2
3
4
5
6
7
8
9
10
|
# Mistake #27: Inefficient map initialization
When creating a map, initialize it with a given length if its length is already known. This reduces the number of allocations and improves performance.
A map provides an unordered collection of key-value pairs in which all the keys are distinct. In Go, a map is based on the hash table data structure. Internally, a hash table is an array of buckets, and each bucket is a pointer to an array of key-value pairs.
If we know up front the number of elements a map will contain, we should create it by providing an initial size. Doing this avoids potential map growth, which is quite heavy computation-wise because it requires reallocating enough space and rebalancing all the elements.
[Source code](https://github.com/teivah/100-go-mistakes/tree/master/src/03-data-types/27-map-init/main_test.go)
|
