def removeNCharsFromCol(data, n, col, start):
    """ Removes n characters from the value of a given column 
        for every row either from the start or the end of
        the string
        :param data: The data to process
        :param n: The number of characters
        :param col: The index of the column to alter
        :param start: Remove from start (True) or end (False)
    """
    for i in range(len(data)):
        try:
            data[i][col] =  data[i][col][n:] if start else data[i][col][:-n]
        except IndexError:
            pass # Empty field
    return data