Why Does Go's `rand.Intn` Seem to Always Return the Same Number?-Golang-php.cn

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Why Does Go's `rand.Intn` Seem to Always Return the Same Number?

Barbara Streisand

Jan 01, 2025 am 07:28 AM

Why Does Go's `rand.Intn` Seem to Always Return the Same Number?

Why Does Go's rand.Intn Consistently Return the Same Number with Every Execution?

The Go standard library includes a rand package for generating random numbers. However, users may encounter an issue where the function rand.Intn, which generates a random integer within a specified range, always returns the same value. This behavior can be attributed to two key factors:

Uninitialized Default Source:
The rand package employs a global source to generate random numbers. By default, this source is uninitialized, leading to the generation of deterministic sequences. To resolve this issue, you must initialize the default source using the rand.Seed function. For instance:
```
rand.Seed(time.Now().UnixNano())
```
Go Playground Caching:
When running code examples on the Go Playground, the output is cached. This caching can mask the true randomness of rand.Intn. To circumvent this issue, ensure that you run the code on a local machine or use a tool that does not cache output, such as go run.

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