python2d数组如何插入x并检索y值？

Question

从昨天开始我一直在寻找答案，但没有运气。所以我有一个1D光谱（.fits）文件，每个波长的通量值。我已经把它们转换成一个2D数组（x，y）=（波长，通量），并想写一个程序来返回给定波长（x）的通量（y）。我试过了：

#modules
import scipy
import numpy as np
import pyfits as pf

#Target Global Vaiables
hdulist_tg = pf.open('cutmask1-2.0001.fits')    
hdr_tg = hdulist_tg[0].header
flux_tg = hdulist_tg[0].data
crval_tg = hdr_tg['CRVAL1']             #Starting wavelength 
cdel_tg = hdr_tg['CDELT1']              #Wavelength axis width 
wave_tg = crval_tg + np.arange(3183)*cdel_tg        #Create an x-axis
wavelist = [6207,6315,6369,6438,6490,6565,6588]

wave_flux=[]
diff = 10
for wave in wave_tg:
    for flux in flux_tg:
        wave_flux.append((wave,flux))           

for item in wave_flux:
    wave = item[0]
    flux = item[1]

#Where I got my actual wavelength that exists in wave_tg
    diffmatch = np.abs(wave - wavelist[0])
    if diffmatch < diff:
        flux_wave = flux  
        diff = diffmatch 
        wavematch = wave

print wavelist[0],flux_wave,wavematch

但是程序总是返回相同的通量值，即使波长不同。请帮忙。。。在

Answer 1

我对你的代码做了一些修改：

• 使用numpy ot创建wave_flux作为ndarray，使用np.hstack()、np.repeat()和{}

• 使用花式索引获取与搜索匹配的值

产生的代码是：

#modules
import scipy
import numpy as np
import pyfits as pf

#Target Global Vaiables
hdulist_tg = pf.open('cutmask1-2.0001.fits')
hdr_tg = hdulist_tg[0].header
flux_tg = hdulist_tg[0].data
crval_tg = hdr_tg['CRVAL1']             #Starting wavelength
cdel_tg = hdr_tg['CDELT1']              #Wavelength axis width
wave_tg = crval_tg + np.arange(3183)*cdel_tg        #Create an x-axis
wavelist = [6207,6315,6369,6438,6490,6565,6588]

wave_flux = np.vstack(( np.repeat(wave_tg, len(flux_tg)),
                        np.tile(flux_tg, len(wave_tg)) )).transpose()

wave_ref = wavelist[0]
diff = 10

print wave_flux[ np.abs(wave_flux[:,0]-wave_ref) < diff ]

它将返回wave_flux的子组，其波值在0列中，通量值在1列中：

^{pr2}$