GoHow-ToBeginner · 3 min read

How to Use Comparison Operators in Go: Syntax and Examples

In Go, you use ==, !=, <, <=, >, and >= to compare values. These operators return a boolean true or false depending on the comparison result.

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Syntax

Comparison operators in Go compare two values and return a boolean result. Here are the operators:

==: equal to
!=: not equal to
<: less than
<=: less than or equal to
>: greater than
>=: greater than or equal to

They work with numbers, strings, and other comparable types.

value1 == value2
value1 != value2
value1 < value2
value1 <= value2
value1 > value2
value1 >= value2

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Example

This example shows how to use comparison operators with integers and strings. It prints the result of each comparison.

package main

import "fmt"

func main() {
    a := 5
    b := 10
    fmt.Println("a == b:", a == b)   // false
    fmt.Println("a != b:", a != b)   // true
    fmt.Println("a < b:", a < b)     // true
    fmt.Println("a <= b:", a <= b)   // true
    fmt.Println("a > b:", a > b)     // false
    fmt.Println("a >= b:", a >= b)   // false

    s1 := "apple"
    s2 := "banana"
    fmt.Println("s1 == s2:", s1 == s2) // false
    fmt.Println("s1 != s2:", s1 != s2) // true
    fmt.Println("s1 < s2:", s1 < s2)   // true (lexicographic)
}

Output

a == b: false a != b: true a < b: true a <= b: true a > b: false a >= b: false s1 == s2: false s1 != s2: true s1 < s2: true

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Common Pitfalls

Common mistakes include:

Using = instead of == for comparison (this is assignment, not comparison).
Comparing incompatible types (e.g., int and string) causes a compile error.
Assuming string comparison is case-insensitive (it is case-sensitive).

package main

import "fmt"

func main() {
    a := 5
    b := 10

    // Wrong: assignment instead of comparison
    // if a = b { // compile error: cannot use assignment in if condition
    //     fmt.Println("Equal")
    // }

    // Correct:
    if a == b {
        fmt.Println("Equal")
    } else {
        fmt.Println("Not equal")
    }

    // Wrong: comparing different types
    // if a == "5" { // compile error: mismatched types int and string
    //     fmt.Println("Equal")
    // }
}

Output

Not equal

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Quick Reference

Operator	Meaning	Example	Result
==	Equal to	5 == 5	true
!=	Not equal to	5 != 3	true
<	Less than	3 < 5	true
<=	Less than or equal to	5 <= 5	true
>	Greater than	7 > 5	true
>=	Greater than or equal to	5 >= 5	true

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Key Takeaways

Use == and != to check if values are equal or not equal.

Use <, <=, >, >= to compare order between values.

Comparison operators return true or false.

Do not confuse = (assignment) with == (comparison).

Only compare values of compatible types.