write python object str to file

Question

class C:
    pass

file = open("newfile.txt", "w")

for j in range(10):
    c = C()
    print c
    file.write(c)

file.close()

Is there anything wrong in this code?
I am new to python and want to write the content that's outputted by 'print c' to file ?

In Python 2, you can use print >>file, c to send the output of a print statement to the file. In Python 3 the print() function uses a keyword argument to do this, i.e. print(c, file=file). A file's write() method does not automatically call an object's __str__() method like print does, so you'd need do it explicitly via file.write(str(c)+'\n'). — martineau
– martineau, Commented May 15, 2015 at 9:52

Martijn Pieters · Accepted Answer · 2015-05-15 09:13:08Z

4

You can use the str() function to convert an object to a string the same way print does:

for j in range(10):
    c = C()
    print c
    file.write(str(c))

This will not include a newline, however. If you need a newline as well, you can manually add one:

file.write(str(c) + '\n')

or use string formatting:

file.write('{}\n'.format(c))

or use the print statement with redirection (>> fileobject):

print >> file, c

answered May 15, 2015 at 9:13

Martijn Pieters

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1 Comment

I'd add a mention to the print_function.