python - Matplotlib 不绘制线图；十字形、圆形和三角形都可以

Question

我正在尝试使用 Matplotlib 绘制一些测量数据。 使用下面显示的代码，我得到了绘图窗口和 GUI，但没有绘制任何绘图。如果我将绘图类型更改为圆形或十字形，效果就很好。

# coding=utf-8
import matplotlib.pyplot as plt
import csv

with open("AgPVP8.2.171g1L#2.csv") as csvfile:
    reader = csv.reader(csvfile, delimiter=",")

    frequencies = []
    phases = []

    for row in reader:
        frequency = float(row[0])
        phase = float(row[4])

        frequencies.append(frequency)
        phases.append(phase)

plt.plot([frequencies], [phases], "b-")
plt.xscale("log")
plt.show()

Answer 1

问题是频率和相位仅存在于 with open(... 的范围内，您必须将其放在以下位置:

import matplotlib.pyplot as plt
import csv

with open("AgPVP8.2.171g1L#2.csv") as csvfile:
    reader = csv.reader(csvfile, delimiter=",")

    frequencies = []
    phases = []

    for row in reader:
        frequency = float(row[0])
        phase = float(row[4])

        frequencies.append(frequency)
        phases.append(phase)
    plt.plot(frequencies, phases, "-b")
    plt.xscale("log")
    plt.show()