Panic: runtime error: index out of range [3] with length 3

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When encountering the error message “panic: runtime error: index out of range [3] with length 3” in Go, it generally means that your program is experiencing an “index out of range” error. This error occurs when you are trying to access or modify an element in a collection (such as an array or slice) using an index that is beyond its range or limit.

In Go, arrays and slices are zero-indexed, which means the first element is at index 0. The index must be between 0 and (length – 1) of the collection. So, if you have an array or slice of length 3, the valid indexes are 0, 1, and 2.

Here’s an example to illustrate this error: 

    
package main

import (
    "fmt"
)

func main() {
    // Creating a slice with length 3
    mySlice := []int{1, 2, 3}

    // Accessing an element with an out-of-range index
    fmt.Println(mySlice[3])
}

In the above example, the “mySlice” slice has a length of 3, so the valid indexes are 0, 1, and 2. However, we are trying to access the element at index 3, which is out of range. This will trigger a panic with the error message “panic: runtime error: index out of range [3] with length 3”.

To resolve this error, ensure that you are using valid indexes within the range of your collection’s length. If you need to access or modify elements beyond the current range, consider resizing the collection or using other appropriate data structures.

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