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

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.

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

For custom format for each column you can set format for whole line. fmt param provides formatting for each line

with open('output.dat') as ofile:
     fmt = '%.0f %02.0f %4.1f %3.0f %4.0f %4.1f %4.0f %4.1f %4.0f'
     np.savetxt(ofile, df.values, fmt=fmt)

Python, Pandas : write content of DataFrame into text File

The question aboves answer helped me. It is not the best, but until to_fwf exists this will do the trick for me...

np.savetxt(r'c:\data\np.txt', df.values, fmt='%d')

or

np.savetxt(r'c:\data\np.txt', df.values, fmt='%10.5f')

pandas.DataFrame.to_string() is all you need. The only trick is how to manage the index.

# Write
# df.reset_index(inplace=True)  # uncomment if the index matters
df.to_string(filepath, index=False)

# Read
df = pd.read_fwf(filepath)
# df.set_index(index_names, inplace=True)  # uncomment if the index matters

If the index is a pandas.Index that has no name, reset_index() should assign it to column "index". If it is a pandas.MultiIndex that has no names, it should be assigned to columns ["level_0", "level_1", ...].

I'm sure you found a workaround for this issue but for anyone else who is curious... If you write the DF into a list, you can write it out to a file by giving the 'format as a string'.format(list indices) eg:

df=df.fillna('')
outF = 'output.txt'      
dbOut = open(temp, 'w')
v = df.values.T.tolist()        
for i in range(0,dfRows):       
    dbOut.write(( \
    '{:7.2f}{:>6.2f}{:>2.0f}{:>4.0f}{:>5.0f}{:6.2f}{:6.2f}{:6.2f}{:6.1f {:>15}{:>60}'\
    .format(v[0][i],v[1][i],v[2][i],v[3][i],v[4][i],v[5][i],v[6][i],v[7][i],v[8][i],\
    v[9][i],v[10][i]) ))
    dbOut.write("\n")
dbOut.close

Just make sure to match up each index with the correct format :)

Hope that helps!