Python 为什么不出现小网格线

我很难让小网格线出现在绘图上。在这方面，我看到了几个这样的问题，建议使用两个网格对象（一个用于大调，一个用于小调），并建议在上添加

minorticks\u

由于某些原因，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()

以下是我得到的：

更改：
ax.minorticks\u on
为
ax.minorticks\u on（）
更改：
ax.minorticks\u on
为
ax.minorticks\u on（）
以下是@M4rtini给出的答案，下面是更正后的代码和新图像：

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()

根据@M4rtini给出的答案，这里是更正后的代码和新图像：

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()