Getting user's QGIS version using PyQGIS

Question

I am trying to write a QGIS plugin, which should work on QGIS 2 and QGIS 3. How can I find out which QGIS version the user is using, so the right imports are made?

Answer 1

In QGis < 3, qgis.core has a QGis object:

>>> from qgis.core import QGis

with various formats of the version string:

>>> QGis.QGIS_VERSION
u'2.18.5'
>>> QGis.QGIS_VERSION_INT
21805

and the release name, fwiw:

>>> QGis.QGIS_RELEASE_NAME
u'Las Palmas'

In versions 3 and above, this module is renamed Qgis for consistency.

There's a bit of a bootstrap problem here, since you can't get the version to figure out if you need to import Qgis or QGis without knowing. So you probably have to wrap it in a try and catch the exception.

try:
    from qgis.core import Qgis
except ImportError:
    from qgis.core import QGis as Qgis

Answer 2

You can call simply try this inside your plugin

from qgis.core import *
print QGis.QGIS_VERSION # will print 2.18.13

I dont know if the function is the same in QGIS 3.0 but for 2.18 this worked. The link to the reference can be found here in the pyqgis documentation

Answer 3

Just a tiny extension to the @Spacedman's answer.

Since QGIS 3.12, there are several methods (version(), versionInt(), and releaseName()) provided via the Qgis class.

from qgis.core import Qgis

print(Qgis.version()) #3.28.10-Firenze
print(Qgis.versionInt()) #32810
print(Qgis.releaseName()) #Firenze

The same what this code does:

from qgis.core import Qgis

print(Qgis.QGIS_VERSION) #3.28.10-Firenze
print(Qgis.QGIS_VERSION_INT) #32810
print(Qgis.QGIS_RELEASE_NAME) #Firenze

Answer 4

We can also use variables:

from qgis.core import QgsExpressionContextUtils 

print(QgsExpressionContextUtils.globalScope().variable('qgis_version'))
# '3.34.10-Prizren'

Or without the slightly annoying town name:

from qgis.core import QgsExpressionContextUtils

print(QgsExpressionContextUtils.globalScope().variable('qgis_version').split('-')[0])
# '3.34.10'

Answer 5

This code worked well on my system:

Input:

from qgis.core import Qgis
print (Qgis.QGIS_VERSION)

Output:

3.30.0-'s-Hertogenbosch