matplotlib lim ticks 设置xy轴的刻度和范围

import numpy as np
import matplotlib.pyplot as plt
x = np.linspace(-np.pi,np.pi,256,endpoint=True)
y = np.sin(x)

plt.plot(x,y,color="red",linestyle="-.")

plt.xlim(-np.pi,np.pi)  # x轴范围
plt.xticks(np.linspace(-np.pi,np.pi,5,endpoint=True))  # x轴的刻度

plt.ylim(-1.0,1.0)  # y轴范围
plt.yticks(np.linspace(-1,1,4,endpoint=True))  # y轴的刻度

plt.show()

help(plt.xlim)

Help on function xlim in module matplotlib.pyplot:

xlim(*args, **kwargs)
    Get or set the *x* limits of the current axes.
    
    ::
    
      xmin, xmax = xlim()   # return the current xlim
      xlim( (xmin, xmax) )  # set the xlim to xmin, xmax
      xlim( xmin, xmax )    # set the xlim to xmin, xmax
    
    If you do not specify args, you can pass the xmin and xmax as
    kwargs, e.g.::
    
      xlim(xmax=3) # adjust the max leaving min unchanged
      xlim(xmin=1) # adjust the min leaving max unchanged
    
    Setting limits turns autoscaling off for the x-axis.
    
    The new axis limits are returned as a length 2 tuple.

help(plt.xticks)

Help on function xticks in module matplotlib.pyplot:

xticks(*args, **kwargs)
    Get or set the *x*-limits of the current tick locations and labels.
    
    ::
    
      # return locs, labels where locs is an array of tick locations and
      # labels is an array of tick labels.
      locs, labels = xticks()
    
      # set the locations of the xticks
      xticks( arange(6) )
    
      # set the locations and labels of the xticks
      xticks( arange(5), ('Tom', 'Dick', 'Harry', 'Sally', 'Sue') )
    
    The keyword args, if any, are :class:`~matplotlib.text.Text`
    properties. For example, to rotate long labels::
    
      xticks( arange(12), calendar.month_name[1:13], rotation=17 )