What's the Most Efficient Way to Retrieve Map Keys in Go?

Efficient Retrieval of Map Keys in Go

While iterating through a map in Go and copying its keys into a slice is a common method for key retrieval, there are more efficient approaches.

Original Approach:

i := 0
keys := make([]int, len(mymap))
for k := range mymap {
    keys[i] = k
    i++
}

Improved Approaches:

1. Setting Capacity:

By setting the capacity of the keys slice to the length of the map, it can eliminate the need for reallocations during the appending process.

keys := make([]int, 0, len(mymap))
for k := range mymap {
    keys = append(keys, k)
}

2. Direct Assignment:

Since the number of keys is known, direct assignment can be used instead of append, resulting in faster execution.

keys := make([]int, len(mymap))

i := 0
for k := range mymap {
    keys[i] = k
    i++
}

Performance Comparison:

The direct assignment approach provides the most efficient key retrieval, outperforming the other methods in speed tests involving maps with a large number of keys.

The above is the detailed content of What's the Most Efficient Way to Retrieve Map Keys in Go?. For more information, please follow other related articles on the PHP Chinese website!