Code examples for obtaining each column of a file through defaultdict in Python

This article mainly introduces Python's method of using defaultdict to read each column of a file, involving Python's file-related reading and traversal operation skills. Friends in need can refer to it

The examples in this article describe the use of Python defaultdict method to read each column of the file. Share it with everyone for your reference, the details are as follows:

#!/usr/bin/python
"""USAGE: python *.py align_SNP_site out_file"""
import sys
#import time
from collections import Counter
#t0=time.clock()
info=open(sys.argv[1])
fast=sys.argv[2]
d_c = {}
d1={}
d2={}
for line in info:
    cols=line.strip().split("\t")
    if cols[0] == "SNP pattern":
        continue
    else:
        d1.setdefault(cols[4],[]).append(cols[1])
        d2.setdefault(cols[7],[]).append(cols[1])
    #d1.setdefault(cols[0],[]).append(cols[5])
    #d2[cols[0]] = "\t".join(cols[0:3])
info.close()
print len(d1)
print len(d2)
my_list=[]
ref_fa = open("some_example.fasta", 'r')
for i in ref_fa.readlines():
    if i.startswith(">"):
        my_list.append(i.rstrip())
ref_fa.close()
print len(my_list)
#sys.exit()
result = open(fast,'w')
for k,v in d1.iteritems():
    cnt1 = Counter(v)
    #print cnt1
    result.write("%s\t" % k)
    for i in sorted(cnt1.items(), key = lambda x: x[1], reverse=True):
        result.write("%s\t%d\t"%(i[0],i[1]))
    result.write("\n")
for k,v in d2.iteritems():
    cnt2 = Counter(v)
    #print cnt2
    result.write("%s\t" % k)
    for i in sorted(cnt2.items(), key = lambda x: x[1], reverse=False):
        result.write("%s\t%d\t"%( i[0],i[1]))
    result.write("\n")
#t1=time.clock()
#print (t1-t0)

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