write variable to file in python

"print" function does not return string, it prints a string to a file. Here is it's signature:

print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)

'myline' is always a 'None' value. Try this instead:

import shlex

socfile=open('test.txt',encoding='utf-8')
csvfile=open('csvfile.csv',mode='w',encoding='utf-8')
for strlist in socfile:
    str=shlex.split(strlist)
    for i in str:
        print(i,',',end='', file=csvfile)
    #csvfile.write("%s" % myline)
    #print(myline)

socfile.close()
csvfile.close()

The input file seems to be a blank separated file with fields optionaly enclosed in double quotes. This is easy to parse with the csv module itself:

with open('samplelogs.txt',encoding='utf-8', newline='') as socfile, \
        open('csvfile.csv',mode='w',encoding='utf-8', newline='') as csvfile:
    rd = csv.reader(socfile, delimiter = ' ', quoting=csv.QUOTE_ALL)   # or "\t" if the delimiter is a tab
    wr = csv.writer(csvfile)
    for row in rd:
        wr.writerow(row)

You can use the csv module with dialects to read and write your files. It'll be less prone to error not rewriting csv-handling code yourself.

Addressing your bug, do this instead:

csvfile.write(','.join(str) + '\n')

Here's your entire program rewritten to be more pythonic. It doesn't include quotes around the fields, but you could add them yourself. But then, just use the csv module and let it do everything for you.

import shlex

with open('test.txt', encoding='utf-8') as socfile:
    with open('csvfile.csv', mode='w', encoding='utf-8') as csvfile:
        csvfile.writelines(','.join(shlex.split(line)) + '\n' for line in socfile)

Here's a complete example using the csv module:

#!/usr/bin/env python3

import csv


def convert(space_separated_file, csv_file):
    class unix_space(csv.unix_dialect):
        def __init__(self):
            self.delimiter = ' '

    input_rows = csv.reader(space_separated_file, dialect=unix_space())
    output = csv.writer(csv_file, dialect='unix')
    output.writerows(input_rows)


def example(in_filename, out_filename):
    with open(in_filename) as f_in:
        with open(out_filename, "w") as f_out:
            convert(f_in, f_out)


def test():
    with open('test.txt', 'w') as f:
        f.write('''"Number" "Date" "Time" "Interface" "Origin" "Type" "Action" "Service" "Source Port" "Source" "Destination" "Protocol" "Rule" "Rule Name" "Current Rule Number" "User" "Information" "Product" "Source Machine Name" "Source User Name"
"176" "16Oct2017" "23:59:00" "eth1" "FWSIN2" "Log" "Accept" "TCP_135" "62005" "Host_10.2.2.68" "10.168.150.135" "tcp" "271" "" "271-SINFW" "" "inzone: Internal; outzone: External; service_id: TCP_135" "Security Gateway/Management" "" ""
''')

    example('test.txt', 'test.csv')

    with open('test.csv') as f:
        print(f.read())


test()

Output:

"Number","Date","Time","Interface","Origin","Type","Action","Service","Source Port","Source","Destination","Protocol","Rule","Rule Name","Current Rule Number","User","Information","Product","Source Machine Name","Source User Name"
"176","16Oct2017","23:59:00","eth1","FWSIN2","Log","Accept","TCP_135","62005","Host_10.2.2.68","10.168.150.135","tcp","271","","271-SINFW","","inzone: Internal; outzone: External; service_id: TCP_135","Security Gateway/Management","",""

Your output:

Number,Date,Time,Interface,Origin,Type,Action,Service,Source Port,Source,Destination,Protocol,Rule,Rule Name,Current Rule Number,User,Information,Product,Source Machine Name,Source User Name
176,16Oct2017,23:59:00,eth1,FWSIN2,Log,Accept,TCP_135,62005,Host_10.2.2.68,10.168.150.135,tcp,271,,271-SINFW,,inzone: Internal; outzone: External; service_id: TCP_135,Security Gateway/Management,,