##################################
#                                #
# Last modified 12/30/2013       # 
#                                #
# Georgi Marinov                 #
#                                # 
##################################

import sys
import string

def run():

    if len(sys.argv) < 3:
        print 'usage: python %s input fieldID outputfilename' % sys.argv[0]
        sys.exit(1)
    
    inputfilename = sys.argv[1]
    ID = int(sys.argv[2])
    outfilename = sys.argv[3]

    outfile = open(outfilename, 'w')
    linelist = open(inputfilename)
    for line in linelist:
        if line.startswith('#'):
            outfile.write(line)
            continue
        fields = line.strip().split('\t')
        value = float(fields[ID])
        if value == 0:
            outfile.write(line)
        else:
            outline = ''
            for i in range(ID):
                outline = outline + fields[i] + '\t'
            outline = outline + str((-1)*value) + '\t'
            for i in range(ID+1,len(fields)):
                outline = outline + fields[i] + '\t'
            outfile.write(outline.strip() + '\n')

    outfile.close()
   
run()