How to Safely Convert an interface{} to an int in Go?

Converting interface{} to int in Go

Your Go code attempts to convert an interface{} value to an int directly, but the conversion fails due to type constraints. The error message indicates that a type assertion is needed for this conversion.

Let's understand the problem and its solution:

Problem:

In the provided code, the variable val is of type interface{}. This means it can hold values of any type. The assignment iAreaId := int(val) attempts to convert the interface{} value to an int. However, this direct conversion is not allowed in Go.

Solution:

To properly convert an interface{} value to a specific type, a type assertion is required. A type assertion provides the compiler with an explicit indication that you want to convert the value to a specific type.

To assert val as an int, use one of the following syntaxes:

1. Panic-prone:

   iAreaId := val.(int)

   If val cannot be converted to int, this approach will panic.

2. Non-panicing:

   iAreaId, ok := val.(int)

   This approach assigns iAreaId to the converted value and ok to a boolean indicating whether the conversion was successful. If the conversion fails, ok will be false.

Understanding the Conversion Rules:

Direct conversion from interface{} to a specific type is not allowed according to the Go language specifications. A type assertion is required to override these rules and explicitly cast the value to the desired type.

The above is the detailed content of How to Safely Convert an interface{} to an int in Go?. For more information, please follow other related articles on the PHP Chinese website!