如何将fft应用于（105,36）文件并读取行并将其存储到（105,18）的新数组中并绘制图形

Question

with open(filename, 'r') as csvfile:
    csvreader = csv.reader(csvfile)

    for row in csvreader:
        rows.append(row)
        # get total number of rows

    print("Total no. of rows: %d" % (csvreader.line_num))

    print('\n rows are:\n')
    for row in rows[:csvreader.line_num]:
        # parsing each column of a row
        for col in row:
            print("%10s" % col),
            print('\n')


def read_rows():
    with open("u.dat") as textFile:
        rows = [[float(digit) for digit in line.split()] for line in textFile]
    return np.array(rows)

rows = read_rows()