我如何控制第二个轴上的刻度？

Question

在此输入图片描述

import numpy as np import matplotlib.pyplot as plt
c=3.1
fig = plt.figure()    
ax1 = fig.add_subplot(111)    
ax2 = ax1.twiny()

xticks0 = np.array([1, 1.03, 1.2, 1.5, 2.06, 3.1, 6.2, 15.5], dtype = 'int_')


xvals = np.arange(3, 16, 0.00001)     
data = xvals     
ax1.plot(xvals, data)

ax1Ticks =xvals
ax2Ticks = xticks0

def tick_function(X):
    V = c/X
    return ["%.2f" % z for z in V]

ax2.set_xticks(ax2Ticks)
ax2.set_xbound(ax1.get_xbound())
ax2.set_xticklabels(tick_function(ax2Ticks))

ax1.set_xlabel("harmonic order") 
ax2.set_xlabel('Wavelength (micrometer)')
ax1.grid(True)
plt.xlim(xmin=3, xmax=15)
plt.tick_params(labelsize = 12 );

plt.show()

我想在顶轴上放置特定的刻度线

但是，没有显示。

我想要的是

底轴3~15阵列

上轴3.1/下轴（3,2.5,2,1.5,1,0.5,0.2）。

Answer 1

如果我理解正确，您想在顶部添加一个单独的刻度和一些自定义标签。

这是您可以做到的方法

1. 定义您想要放置标记的“真实位置”。这是 1, 1.03, ...
2. 为这些职位定义“自定义标签”。应用您的函数

   tick_function

   将添加自定义标签

这是可以提供帮助的代码部分：

ax2 = ax1.twiny() # Secondary (top) axis
ax2_ticks = np.array([1, 1.03, 1.2, 1.5, 2.06, 3.1, 6.2, 15.5])
ax2_labels = [f"{x:.2f}" for x in ax2_ticks]  


ax2.set_xticks(ax2_ticks)  
ax2.set_xticklabels(ax2_labels)
ax2.set_xlabel("Top Axis: Wavelength (micrometer)")

在这里我修复了整个代码，似乎这是必要的：

import numpy as np
import matplotlib.pyplot as plt


# Constants
c = 3.1
xvals = np.arange(3, 20, 0.00001)  # Primary axis values


fig, ax1 = plt.subplots(figsize=(12, 10))  # Primary axis (bottom)
ax2 = ax1.twiny() # Secondary (top) axis


ax1_ticks = np.arange(3, 16)  
ax1.set_xticks(ax1_ticks)  
ax1.set_xticklabels(ax1_ticks)  
ax1.set_xlabel("Botton Axis: Harmonic Order")


ax2_ticks = np.array([1, 1.03, 1.2, 1.5, 2.06, 3.1, 6.2, 15.5])
ax2_labels = [f"{x:.2f}" for x in ax2_ticks]  


ax2.set_xticks(ax2_ticks)  
ax2.set_xticklabels(ax2_labels)
ax2.set_xlabel("Top Axis: Wavelength (micrometer)")


ax1.set_xlim(3, 16) 
ax2.set_xbound(ax1.get_xbound()) 

# Add if you need vertical lines
ax1.grid(True, which='both', axis='x') 
ax2.grid(True, which='both', axis='x') 


ax1.plot(xvals, xvals) 


plt.show()