How to check if a Golang map contains a key
Gutha Vamsi KrishnaOverview
In this shot, we will learn to check if the Golang map contains a key.
We can use if statements in Golang to check if a key is present in the map or not.
Syntax
if val, ok := map["key"]; ok {
//do
}else{
}
Return value
If a map has key, then ok has the bool value true, and val contains a value of that key.
We can have an else statement to handle if the map doesn’t contain the required key.
Example
In the example below, we have a map students, which contains student names as keys and their age as the value.
We will get the age of a student and handle the else case if a student isn’t found.
Code
package main
//program execution starts here
func main(){
//declare a map
students := map[string]int{
"john": 10,
"james": 12,
"mary":13,
}
//check if john is present in map
if val, ok := students["john"]; ok {
print(val)
}else{
print("No record found")
}
}
Explanation
In the above code:
-
Line 4: We start program execution from the
main()function in Golang. -
Line 7: We declare and initialize the map
studentswhere the key is ofstringtype, which holds student’s name, and value ofinttype, which holds student’s age. -
Line 14: We check if map
studentsand a keyjohnis present or not.- Line 15: If present, it displays the value, which is the student’s age.
- Line 17: If not present, it prints
No record found.
When we run the above code snippet, we see the output as 10, which is john's age.
If we try to pass student name robert, which is not in the map students, then the output is No record found. This is because robert is not present in the map students.
package main
//program execution starts here
func main(){
//declare a map
students := map[string]int{
"john": 10,
"james": 12,
"mary":13,
}
//check if john is present in map
if val, ok := students["robert"]; ok {
print(val)
}else{
print("No record found")
}
}
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