绘制在同一轴python上的for循环内生成的多个图

Question

我的代码如下，问题是没有一个情节，我得到242个情节。我尝试将plt.show()置于循环之外，但它不起作用。

import numpy as np
import matplotlib.pyplot as plt
import csv

names = list()

with open('selected.csv','rb') as infile:
    reader = csv.reader(infile, delimiter = ' ')
    for row in reader:
        names.append(row[0])

names.pop(0)

for j in range(len(names)):
    filename = '/home/mh/Masters_Project/Sigma/%s.dat' %(names[j])
    average, sigma = np.loadtxt(filename, usecols = (0,1), unpack = True, delimiter = ' ')
    name = '%s' %(names[j]) 
    plt.figure()
    plt.xlabel('Magnitude(average)', fontsize = 16)
    plt.ylabel('$\sigma$', fontsize = 16)
    plt.plot(average, sigma, marker = '+', linestyle = '', label = name)
plt.legend(loc = 'best')
plt.show()

Answer 1

您的问题是，您使用plt.figure()每次迭代都会创建一个新数字。从for循环中删除此行，它应该可以正常工作，如下面的简短示例所示。

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(10)

for a in [1.0, 2.0, 3.0]:
    plt.plot(x, a*x)

plt.show()

Answer 2

让我稍微改进你的代码：

import numpy as np
import matplotlib.pyplot as plt

# set the font size globally to get the ticklabels big too:
plt.rcParams["font.size"] = 16

# use numpy to read in the names
names = np.genfromtxt("selected.csv", delimiter=" ", dtype=np.str, skiprows=1)

# not necessary butyou might want to add options to the figure
plt.figure()

# don't use a for i in range loop to loop over array elements
for name in names:
    # use the format function
    filename = '/home/mh/Masters_Project/Sigma/{}.dat'.format(name)

    # use genfromtxt because of better error handling (missing numbers, etc)
    average, sigma = np.genfromtxt(filename, usecols = (0,1), unpack = True, delimiter = ' ')

    plt.xlabel('Magnitude(average)')
    plt.ylabel('$\sigma$')
    plt.plot(average, sigma, marker = '+', linestyle = '', label = name)

plt.legend(loc = 'best')
plt.show()