How do I remove the commas, quotes, and parentheses from an exported python list?

Question

You guys were super helpful with my last newbie question so I figured I would give it another shot. Right now, my Python 3 code takes data from a CSV file, stores the data as a list, creates permutations of that data, and exports it back out into a new csv file in a column format. Unfortunately, the format of the exported list is not the best for what I need it for. My question is: How do I remove the commas, brackets, and parenthesis from the exported list in python?

How it Looks Now:

('Hello', 'World', 'How')

('Hello', 'World', 'Are')

('Hello', 'How', 'World')

How I would like it to look:

Hello World How

Hello World Are

Hello How World

Here is the code I am using, does anyone have any advice or suggestions? I am trying to learn so any extra insight would be much appreciated!

import csv
import itertools
with open('/users/Desktop/pythondata.csv', 'r') as f:
   reader = csv.reader(f)
   J = []
   for row in reader:
      J.extend(row)
C = list(itertools.permutations(J, 3))
with open('THISISATEST.csv','w')as f:
   writer=csv.writer(f,lineterminator='\n')
   for val in C:
       writer.writerow([val])`

PS -- Please forgive me if this is not formatted correctly, I am new to the board!

Answer 1

Your question:

I recommend that you just use the join method to get the single string you are looking for. You could try:

with open('test.csv', 'w') as a_file:
    for result in C:
        result = ' '.join(result)
        a_file.write(result + '\n')

Basically, the join method called on a the string ' ' (a single space) will take each item in its argument (a single result from your permutations) and add them together in a single string separated by whatever that first string was (the single space). This site gives a simple, illustrative example.

The join method is called with the syntax '[separator]'.join([list of items to join]) , so if you just wanted to mash everything together into one string with no spaces, you could call it on an empty string: ''.join([my list]) .

Since you do not need a comma-separated file (CSV), you can simplify things by just using the a_file.write method as shown. If you use the CSV writer in this code you will get commas between every letter.

Answer 2

I don't know if you are aware of regular expressions but using python's ' re ' module should give you what you are looking for:

    import re
    strs = "('Hello', 'World', 'How')"

    #creates list of strings that match the regular expression
    words = re.findall(r"\'([A-Za-z]+)\'", strs)

    #joins all of the elements of the word array into a string separated by a space
    outputString = " ".join(words)

    #output is "Hello World How"
    print outputString

Answer 3

Since you have tuples, there's an easier way. You don't need csv to export a space-delimited file.

import csv
import itertools
with open('pythondata.csv', 'r') as f:
    reader = csv.reader(f)
    J = []
    for row in reader:
        J.extend(row)
C = itertools.permutations(J, 3)
with open('THISISATEST.txt','w') as f:
    f.write('\n'.join(' '.join(y for y in x) for x in C))

Answer 4

If anyone is still searching for this as I was when try this, (python 3.x). My aim was to list on separate lines all possible permutations of a 9 digit number.

the line string = ''.join(str(char) for char in line) was the winner

import sys, itertools

f = open('path to file', 'w') #I was using a .txt file

permutations = (list(itertools.permutations([1,2,3,4,5,6,7,8,9], 9)))

for line in permutations:
    string = ''.join(str(char) for char in line)
    f.write(string + '\n')            

f.close()