Using .write function with multiple arguments for writing to a txt file - Python

Question

I am trying to write the following loop to a .txt file (in addition to printing the output to terminal). On doing so I get an error that says:

> TypeError:function takes exactly 1 argument (2 given)

I understand what the error is trying to convey, but is there a way to work around this. I do need the labels and the results output to the .txt file just like they are printed on the terminal

Here is the code I am using:

out_write = open(write_to, 'wb')

for arr in top_k:
    print(labels[arr], results[arr])
    out_write.write(labels[arr], results[arr])
print ("\n\n\n")
out_write("\n\n\n")
out_write.close()

I am working in python 2.7

out_write.write('{} {}'.format(labels[arr], results[arr])) — Burhan Khalid
– Burhan Khalid, Commented Nov 22, 2017 at 2:36
Make a single string (however you like to do that: concatenation, %, .format(), f-strings) or use two calls to .write() — kindall
– kindall, Commented Nov 22, 2017 at 2:39

kindall · Accepted Answer · 2017-11-22 02:54:11Z

6

Python offers many solutions to this problem. You can combine your arguments to make a single string using several methods:

Convert to string and concatenate
out_write.write(str(labels[arr]) + " " + str(results[arr]) + "\n")
Old-school string interpolation using %
out_write.write("%s %s\n" % (labels[arr], results[arr]))
str.format()
out_write.write("{} {}\n".format(labels[arr], results[arr]))
f-strings, the new hotness
out_write.write(f"{labels[arr]} {results[arr]}\n")

Or you can use print() itself:

print(labels[arr], results[arr], file=out_write)

To avoid the need to specify the file parameter in every call to print(), you can use functools.partial:

file_out = functools.partial(print, file=out_write)
file_out(labels[arr], results[arr])

Or a lambda!

file_out = lambda *args: print(*args, file=out_write)
file_out(labels[arr], results[arr])

Why not write a function that prints and writes at the same time? One call does it all!

out = lambda *args: print(*args) and print(*args, file=out_write)

edited Nov 22, 2017 at 2:54

answered Nov 22, 2017 at 2:50

kindall

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5 Comments

Veejay Over a year ago

Thank you! I took your str.format() advice, but it outputs the text onto the same line. Im sure I'm missing something very basic to go into a new line after it prints a "label result" combo. Thanks!

kindall Over a year ago

Sorry, forgot to put newlines into the format strings. I just edited my answer to add those..

Veejay Over a year ago

Perfect! That did it. Just one more thing, I am running this loop over multiple files, so essentially this for loop gets run multiple times but I think my code only prints the outputs to the for loop once (on the text file), the terminal has as many for loops as there are files in my dir since I am looping over them. What would a reason for this not being reflected in the out.txt? Thanks :)

kindall Over a year ago

I'd ask a new question for that.

Veejay Over a year ago

Figured it out, its essentially just out_write = open(write_to, 'a') instead of the 'wb'!

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