import numpy
import pyfits
import math

fitsfile = pyfits.open('VHI21PrimaryBeamCorrected.fits')

outfile = 'NanCorrected.fits'

image = fitsfile[0].data
header = fitsfile[0].header

print image.shape

sizex = image.shape[1]
sizey = image.shape[2]

for i in range(0,sizex):
	for j in range(0,sizey):
		#print image[i,j]
		if 'nan' in str(image[0,i,j]):
			image[0,i,j] = 0.0
			
FitsFile = pyfits.writeto(outfile, image, header=header)