Any check to see if the code written is in python 2.7 or 3 and above?

Question

I have a buggy long python project that I am trying to debug. Its messy and undocumented. I am familiar with python2.7. There are no binaries in this project. The straight f

Answer 1

Attempt to compile it. If the script uses syntax specific to a version then the compilation will fail.

$ python2 -m py_compile foo.py
$ python3 -m py_compile foo.py

Answer 2

The following statements indicate Python 2.x:

import exceptions

for i in xrange(n):
  ...

print 'No parentheses'

# raw_input doesn't exist in Python 3
response = raw_input()

try:
   ...
except ValueError, e:
   # note the comma above
   ...

These suggest Python 2, but may occur as old habits in Python 3 code:

'%d %f' % (a, b)

# integer divisions
r = float(i)/n # where i and n are integer
r = n / 2.0

These are very likely Python 3:

# f-strings
s = f'{x:.3f} {foo}'

# range returns an iterator
foo = list(range(n))

try:
   ...
except ValueError as e:
   # note the 'as' above
   ...

Answer 3

add this line to the file:

help()

this should automatically print the version along with the default help interface. remember to remove it later.

Answer 4

Use this in your code:

import platform
print platform.python_version()

outputs a string: 2.7.10