import os
import sys

#Reads outfiles from Pythia hadronization procedure, extracts final post-matching xsec value
#and prints value in an output textfile, so that many output xsec values for a single
#jet mult. and variation can be analyzed
#Note: Reads in files in specified folders in the form of e.g. "2j_0108/job_2j_0108_1.out"

#######################
numjobs = 50
jetnum = 0
variation = 108
#######################

outfileNameTemp = "%dj_0%d_xsec.txt" % (jetnum, variation)
outfileName = str(outfileNameTemp)
outfile = open(outfileName, "w")
print "outfile name is "+outfileName

# file numbering starts from 1
for x in range(1, numjobs+1):
    filenameTemp = "%dj_0%d/job_%dj_0%d_%d.out" % (jetnum, variation, jetnum, variation, x)
    filename = str(filenameTemp)
    
    file = open(filename)
    for line in file.readlines():
        if "After filter: final cross section =" in line:
            #print line
            line = line.split(' = ')[1]
            line = line.split(' +- ')[0]
            print line
            outfile.write(line + '\n')
    file.close()

outfile.close()