def iter_loadtxt(filename, delimiter=',', skiprows=0, read_range=None,
    dtype=float):
    """
    Read the file line by line and convert it to Numpy array.
    :param delimiter: character
    :param skiprows : int
    :param read_range: [int, int] or None. set it to None and the function will read the whole file.
    :param dtype: type
    """

def iter_func():
    with open(filename, 'r') as infile:
        for _ in range(skiprows):
            next(infile)
reading rows of big csv file in python