How can I check for Python version in a program that uses new language features?
You can test using eval
:
try:
eval("1 if True else 2")
except SyntaxError:
# doesn't have ternary
Also, with
is available in Python 2.5, just add from __future__ import with_statement
.
EDIT: to get control early enough, you could split it into different .py
files and check compatibility in the main file before importing (e.g. in __init__.py
in a package):
# __init__.py
# Check compatibility
try:
eval("1 if True else 2")
except SyntaxError:
raise ImportError("requires ternary support")
# import from another module
from impl import *
Have a wrapper around your program that does the following.
import sys
req_version = (2,5)
cur_version = sys.version_info
if cur_version >= req_version:
import myApp
myApp.run()
else:
print "Your Python interpreter is too old. Please consider upgrading."
You can also consider using sys.version()
, if you plan to encounter people who are using pre-2.0 Python interpreters, but then you have some regular expressions to do.
And there might be more elegant ways to do this.
Try
import platform platform.python_version()
Should give you a string like "2.3.1". If this is not exactly waht you want there is a rich set of data available through the "platform" build-in. What you want should be in there somewhere.