1. line chart

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2 * np.pi, 100)
y1, y2 = np.sin(x), np.cos(x)

plt.plot(x, y1)
plt.plot(x, y2)

plt.title('line chart')
plt.xlabel('x')
plt.ylabel('y')

plt.show()

2. 图例

plot的时候指定label,然后调用legend方法可以绘制图例。例如:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2 * np.pi, 100)
y1, y2 = np.sin(x), np.cos(x)

plt.plot(x, y1, label='y = sin(x)')
plt.plot(x, y2, label='y = cos(x)')
plt.legend()
plt.show()

legend方法可接受一个loc关键字参数来设定图例的位置,可取值为数字或字符串:

  • 0: ‘best’
  • 1: ‘upper right’
  • 2: ‘upper left’
  • 3: ‘lower left’
  • 4: ‘lower right’
  • 5: ‘right’
  • 6: ‘center left’
  • 7: ‘center right’
  • 8: ‘lower center’
  • 9: ‘upper center’
  • 10: ‘center’

3. 线的样式

(1)颜色

plot方法的关键字参数color(或c)用来设置线的颜色。可取值为:

  • 颜色名称或简写
    • b: blue
    • g: green
    • r: red
    • c: cyan
    • m: magenta
    • y: yellow
    • k: black
    • w: white
  • #rrggbb
  • (r, g, b) 或 (r, g, b, a),其中 r g b a 取均为[0, 1]之间
  • [0, 1]之间的浮点数的字符串形式,表示灰度值。0表示黑色,1表示白色

(2)样式

plot方法的关键字参数linestyle(或ls)用来设置线的样式。可取值为:

  • -, solid
  • --, dashed
  • -., dashdot
  • :, dotted
  • '', ' ', None

(3)粗细

设置plot方法的关键字参数linewidth(或lw)可以改变线的粗细,其值为浮点数。

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2 * np.pi, 100)
y1, y2 = np.sin(x), np.cos(x)

plt.plot(x, y1, c='r', ls='--', lw=3)
plt.plot(x, y2, c='#526922', ls='-.')
plt.show()

4. marker

以下关键字参数可以用来设置marker的样式:

  • marker
  • markeredgecolor 或 mec
  • markeredgewidth 或 mew
  • markerfacecolor 或 mfc
  • markerfacecoloralt 或 mfcalt
  • markersize 或 ms

其中marker可取值为:

  • '.': point marker
  • ',': pixel marker
  • 'o': circle marker
  • 'v': triangle_down marker
  • '^': triangle_up marker
  • '<': triangle_left marker
  • '>': triangle_right marker
  • '1': tri_down marker
  • '2': tri_up marker
  • '3': tri_left marker
  • '4': tri_right marker
  • 's': square marker
  • 'p': pentagon marker
  • '*': star marker
  • 'h': hexagon1 marker
  • 'H': hexagon2 marker
  • '+': plus marker
  • 'x': x marker
  • 'D': diamond marker
  • 'd': thin_diamond marker
  • '|': vline marker
  • '_': hline marker

例如:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2 * np.pi, 10)
y1, y2 = np.sin(x), np.cos(x)

plt.plot(x, y1, marker='o', mec='r', mfc='w')
plt.plot(x, y2, marker='*', ms=10)
plt.show()

另外,marker关键字参数可以和color以及linestyle这两个关键字参数合并为一个字符串。例如:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 2 * np.pi, 10)
y1, y2 = np.sin(x), np.cos(x)

plt.plot(x, y1, 'ro-')
plt.plot(x, y2, 'g*:', ms=10)
plt.show()