how to tell a loop to ignore last element in a list python code example

Example: how to remove the very last character of a text file in python

file.truncate(file.tell - 1)
#explanation - the function truncate will resize the file to the 
#full size - 1 and that means it will remove the last character
#if you need to do that while you are reading/writing somewhere using
#seek() you can use this function ->
def get_size(fileobject):
    fileobject.seek(0,2) # move the cursor to the end of the file
    size = fileobject.tell()
    return size
#and then
fsize = get_size(file)
file.truncate(fsize - 1)