JSON dump big list containing dict, text, datetime and ints gives "TypeError: 'str' does not support the buffer interface"

Question

Using Python 3.2 64 bit on Windows 7 64 bit.

f = open("raw_data/results.json", "wb")
json.dump(dictio, f)
f.close()

Gives error:

Traceback (most recent call last):
  File ".\calc_stats_friendly_data.py", line 22, in <module>
    main()
  File ".\calc_stats_friendly_data.py", line 18, in main
    json.dump(races, f)
  File "C:\Python32\lib\json\__init__.py", line 179, in dump
    fp.write(chunk)
TypeError: 'str' does not support the buffer interface

I have no idea what goes wrong. Using pickle works fine! But I have to use JSON... Tips for finding the problem? The list is big. Saving it with pickle it takes 56 MB.

Answer 1

You're opening the file for binary writing. Open it using "w" as a mode only.