从选定的行数中找到局部最大值

Question

我的代码的重要部分是使行的最大值从3500埃（天文单位）到7000埃不等。但是，我的函数正在调用的最大值超出了范围。如何在文件中调用一定范围的行？

%matplotlib notebook 
import numpy as np                           #import python tools
import matplotlib.pyplot as plt
import math

file1 = 'spectra1.dat'                #call the first file
spectra1 = np.loadtxt(file1, skiprows=3)

fig= plt.figure()                            #plotting the data for the figure below
plt.title('spectral atlas', fontname="times new roman", fontsize=15)
#title
axes=fig.add_subplot(111)                    #create dimensions for graph
plt.ylabel('Normalized Flux ', fontname="times new roman") #Label for Y axis
plt.xlabel('Wavelength ($\AA$)', fontname="times new roman")        #Label for X axis 
plt.xlim(3500,7000)
plt.ylim(0,3)

ymax = max(spectra1[:,1])
print(ymax)
norminc1 = (spectra1[:,1]/ymax)+1

axes.plot(spectra1[:,0], norminc1, label= 'normalized flux of spectra1')

plt.legend(loc=1, prop={'size': 7})          #create legend, moving it to top right and decreasing size
plt.show()