在golang内部如何进行映射？ [重复]

Question

This question already has an answer here:

• Meaning of underscore (blank identifier) in Go [duplicate] 5 answers

Here is specific example

func main(){    
m := make(map[string]int)  
m["k1"] = 7  

_, prs := m["k2"]   
fmt.Println(prs)  
}

What does "_" signifies here?
Rest is clear to me.

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Answer 1

See dokumentation. Your statement:

_, prs := m["k2"]

is doing two things at the same time. A) Checking whether a key/value is present in the map and B) is retrieves the value. "prs" is a boolean indicating whether the value was present for the key "k2" or not.

Thus, if you only want to check if a key/value is present in the map and do not care to use the value, you can use the "_" to ignore the value and only use the "prs" boolean.