我正在尝试从Flexible Image Transport System（FITS）文件中绘制一些数据，我想知道是否有人知道如何将焦点放在绘图轴的某些区域上。下面是一些示例代码：

import pyfits
from matplotlib import pyplot as plt
from matplotlib import pylab
from pylab import *
#Assuming I have my data in the current directory
a = pyfits.getdata('fits1.fits')
x = a['data1'] # Let's assume data1 is the column: [0, 1, 1.3, 1.5, 2, 4,  8]
y = a['data2'] # And data2 is the column:          [0, 0.5, 1, 1.5, 2, 2.5,3]
plt.plot(x,y)

我怎么能只画出x轴上从[1.3 to 4]开始的区域呢？