How save a array to text file in python?

Question

I have a array of this type:

xyz = [['nameserver','panel'], ['nameserver','panel']]

How can I save this to an abc.txt file in this format:

nameserver panel
nameserver panel

I tried this using, on iterating over each row:

np.savetxt("some_i.txt",xyz[i],delimiter=',');

It's showing this error:

TypeError: Mismatch between array dtype ('<U11') and format specifier 
('%.18e')

your original list contains nameservers, but saved file -- nameserver (no s at the end) — lenik
– lenik, Commented Aug 15, 2018 at 14:32
Can you walk through your list of lists and print it to the screen? (Just trying to work out what you are having trouble with) — doctorlove
– doctorlove, Commented Aug 15, 2018 at 14:33
There's a default format speicifer: fmt='%.18e' for numpy's savetxt method, which is for savinf floating point numbers not strings. Hence the error. — doctorlove
– doctorlove, Commented Aug 15, 2018 at 14:46

ybl · Accepted Answer · 2018-08-15 14:37:40Z

41

This is a possible solution:

data = [['nameservers','panel'], ['nameservers','panel']]

with open("output.txt", "w") as txt_file:
    for line in data:
        txt_file.write(" ".join(line) + "\n") # works with any number of elements in a line

answered Aug 15, 2018 at 14:37

ybl

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Comments

Agile Bean · Accepted Answer · 2024-05-02 16:36:36Z

19

Probably the simplest method is to use the json module, and convert the array to list in one step:

import json

with open('output.txt', 'w') as filehandle:
    json.dump(array.toList(), filehandle)

Advantage: Using the json format allows interoperability between many different systems.

edited May 2, 2024 at 16:36

answered Jul 11, 2019 at 4:57

Agile Bean

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4 Comments

erfelipe Over a year ago

Beautiful method.

Gilles Pion Over a year ago

the "toList" method on an array variable throws the following exception for me: *** AttributeError: 'list' object has no attribute 'toList'

Vikram Murthy Over a year ago

this should be the first answer .. the previous answer is just too hacky and also needs lots of code checks while reading off the file while recreating it

pbies Jul 18 at 15:35

To load: with open("output.txt","r") as fh: array=json.load(fh).

Tomerikoo · Accepted Answer · 2021-11-15 09:33:03Z

8

Use csv.writer:

import csv

data = [['nameservers','panel'], ['nameservers','panel']]

with open('tmp_file.txt', 'w') as f:
    csv.writer(f, delimiter=' ').writerows(data)

tmp_file.txt would now like this

nameservers panel
nameservers panel

edited Nov 15, 2021 at 9:33

Tomerikoo

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answered Aug 15, 2018 at 15:04

Sunitha

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Comments

user9455968 · Accepted Answer · 2018-08-15 14:34:44Z

4

One of many possibilities:

stuff = [['nameservers','panel'], ['nameservers','panel']]
with open("/tmp/out.txt", "w") as o:
    for line in stuff:
        print("{} {}".format(line[0], line[1]), file=o)

answered Aug 15, 2018 at 14:34

user9455968

Comments

modesitt · Accepted Answer · 2018-08-15 14:33:35Z

3

You can just write it out to a file directly.

with open('outfile.txt', 'w') as f:
    f.write('\n'.join([' '.join(l2) for l2 in l1]))

where l1 is the list you gave.

answered Aug 15, 2018 at 14:33

modesitt

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4 Comments

lenik Over a year ago

don't use l in variable names

lenik Over a year ago

makes things unreadable, especially when mixed with 1, l1ll11l1l111l1l1ll -- can you read this?

Psytho Over a year ago

@lenik So i can't name my variable location or letter? You shouldn't use l as a single character variable name, there are no other limitations for this (PEP-8)

modesitt Over a year ago

12 is not a variable name... @lenik ;) and can not be joined

Sayed Sadat · Accepted Answer · 2024-01-04 00:39:46Z

1

Another solution could be:

# import packages
from numpy import asarray
from numpy import savetxt

# Lets say you have the data in `y`
data = asarray(y)

# Save the file
savetxt('data.csv', data, delimiter=',')

answered Jan 4, 2024 at 0:39

Sayed Sadat

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