Python Pandas, write DataFrame to fixed-width file (to_fwf?)

python pandas fixed-width
jkmacc picture jkmacc · May 10, 2013 · Viewed 14.6k times · Source

I see that Pandas has read_fwf, but does it have something like DataFrame.to_fwf? I'm looking for support for field width, numerical precision, and string justification. It seems that DataFrame.to_csv doesn't do this. numpy.savetxt does, but I wouldn't want to do:

numpy.savetxt('myfile.txt', mydataframe.to_records(), fmt='some format')

That just seems wrong. Your ideas are much appreciated.

Answer

Matt Kramer picture Matt Kramer · Mar 13, 2016

Until someone implements this in pandas, you can use the tabulate package:

import pandas as pd
from tabulate import tabulate

def to_fwf(df, fname):
    content = tabulate(df.values.tolist(), list(df.columns), tablefmt="plain")
    open(fname, "w").write(content)

pd.DataFrame.to_fwf = to_fwf

Related questions

How do I read a fixed width format text file in pandas?

I just got my hands on pandas and am figuring out how I can read a file. The file is from the WRDS database and is the SP500 constituents list all the way back to the 1960s. I checked the …

Read More
How to select rows from a DataFrame based on column values

How can I select rows from a DataFrame based on values in some column in Pandas? In SQL, I would use: SELECT * FROM table WHERE colume_name = some_value I tried to look at Pandas' documentation, but I did not …

Read More
Renaming columns in pandas

I have a DataFrame using pandas and column labels that I need to edit to replace the original column labels. I'd like to change the column names in a DataFrame A where the original column names are: ['$a', '$…

Read More