Python pandas: output dataframe to csv with integers

Question

I have a pandas.DataFrame that I wish to export to a CSV file. However, pandas seems to write some of the values as float instead of int types. I couldn't not find how to change this behavior.

Building a data frame:

df = pandas.DataFrame(columns=['a','b','c','d'], index=['x','y','z'], dtype=int) x = pandas.Series([10,10,10], index=['a','b','d'], dtype=int) y = pandas.Series([1,5,2,3], index=['a','b','c','d'], dtype=int) z = pandas.Series([1,2,3,4], index=['a','b','c','d'], dtype=int) df.loc['x']=x; df.loc['y']=y; df.loc['z']=z 

View it:

>>> df     a   b    c   d x  10  10  NaN  10 y   1   5    2   3 z   1   2    3   4 

Export it:

>>> df.to_csv('test.csv', sep='\t', na_rep='0', dtype=int) >>> for l in open('test.csv'): print l.strip('\n')         a       b       c       d x       10.0    10.0    0       10.0 y       1       5       2       3 z       1       2       3       4 

Why do the tens have a dot zero ?

Sure, I could just stick this function into my pipeline to reconvert the whole CSV file, but it seems unnecessary:

def lines_as_integer(path):     handle = open(path)     yield handle.next()     for line in handle:         line = line.split()         label = line[0]         values = map(float, line[1:])         values = map(int, values)         yield label + '\t' + '\t'.join(map(str,values)) + '\n' handle = open(path_table_int, 'w') handle.writelines(lines_as_integer(path_table_float)) handle.close() 

Answer 1

The answer I was looking for was a slight variation of what @Jeff proposed in his answer. The credit goes to him. This is what solved my problem in the end for reference:

import pandas df = pandas.DataFrame(data, columns=['a','b','c','d'], index=['x','y','z']) df = df.fillna(0) df = df.astype(int) df.to_csv('test.csv', sep='\t')