为什么没有出现次要网格线

Question

我很难让较小的网格线出现在情节上。我已经看到了一些关于此的 SO 问题，this one 建议使用两个网格对象（一个用于主要对象，一个用于次要对象），this one 建议还添加minorticks_on。

由于某种原因，当我使用下面的代码时，小网格线仍然没有出现，请任何人解释一下：

from __future__ import division
from matplotlib import pyplot as plt
from math import log, sqrt

x = range(1, 20)
x_lin = x
x_log = [log(i) for i in x]

x2 = [sqrt(i) for i in x]
x2_exp = x

ax = plt.subplot(1,1,1)
p1 = ax.plot(x, x_lin, 'g--', label='linear', linewidth=2)
p2 = ax.plot(x, x_log, 'b-', label='log', linewidth=3)
p3 = ax.plot(x2, x2_exp, 'r-', label='exp', linewidth=3)
l1 = ax.legend()
g1 = ax.grid(b=True, which='both', color='k', linestyle='-')
g2 = ax.grid(b=True, which='minor', color='k', linestyle='--')
ax.minorticks_on
plt.show()

这是我得到的：

Answer 1

按照@M4rtini 给出的答案，这里是更正的代码和新图像：

from __future__ import division
from matplotlib import pyplot as plt
from math import log, sqrt

x = range(1, 20)
x_lin = x
x_log = [log(i) for i in x]

x2 = [sqrt(i) for i in x]
x2_exp = x

ax = plt.subplot(1,1,1)
p1 = ax.plot(x, x_lin, 'g--', label='linear', linewidth=2)
p2 = ax.plot(x, x_log, 'b-', label='log', linewidth=3)
p3 = ax.plot(x2, x2_exp, 'r-', label='exp', linewidth=3)
l1 = ax.legend()
g1 = ax.grid(b=True, which='major', color='k', linestyle='-', linewidth=0.5)
g2 = ax.grid(b=True, which='minor', color='k', linestyle='-', linewidth=0.2)
ax.minorticks_on()
plt.show()

Answer 2

更改：ax.minorticks_on 为 ax.minorticks_on()