Appending a matrix to an existing file using numpy

Question

I'm trying to add a matrix to an existing csv file. Following this link, I wrote the following code,

f_handle = file(outfile+'.x.betas','a')
np.savetxt(f_handle,dataPoint)
f_handle.close()

where I have imported numpy as np, i.e.

import numpy as np

But I get this error:

f_handle = file(outfile+'.x.betas','a')
TypeError: 'str' object is not callable

I can't figure out what the problem seems to be. Please help :)

Answer 1

It looks like you might have defined a variable named file which is a string. Python then complains that str objects are not callable when it encounters

file(...)

You can avoid the issue by, as Bitwise says, changing file to open.

You could also avoid the problem by not naming a variable file.

Nowadays, the best way to open a file is by using a with-statement:

with open(outfile+'.x.betas','a') as f_handle:
    np.savetxt(f_handle,dataPoint)

This guarantees that the file is closed when Python leaves the with-suite.