How to delete a struct from an array without leaving a gap? [duplicate]

Question

I want to delete a struct from an array. The order doesn't matter to me so I want to do something like following where you take the last element in the array to replace the element I want to delete so that there are no gaps in the array.

mapping (address => File[]) myFiles;

function deleteFile(uint _index) public {
    require(_index >= 0, "The index cannot be a negative number");
    
    File[] memory files = myFiles[msg.sender];
    require(_index < files.length, "The index is out of bound");
        
    if (files.length == 1) {
        files.pop();
    } else {
        File memory file = files[files.length - 1];
        files[_index] = files;
        files.pop();
    }
}

However, pop is not available for struct arrays. I also cannot use files.length -- since length is read-only. How do I achieve this?