I’m creating a new conda environment with no additional packages.
It is interesting to note the difference in the python interpreter version installed with a small change in the conda create syntax…
conda create --name test python=3.11
…installs python 3.11.9 as expected.
However but putting a double == rather than a single = when specifying the python version…
conda create --name test python==3.11
…does not throw any errors but creates an environment containing python 3.11.0, not the 3.11.9 that I was expecting.
This is consistent across 3.9, 3.10, 3.11 and 3.12, all install patch version 0.
I assume the double == is not the correct syntax and that this is not an intended behaviour but this is not caught and certainly confused me for a while.
Windows 10, conda version 23.11.0
It is definitely desired behavior and not a bug: Specifying the version with = is considered a “fuzzy constraint” while == is considered an “exact constraint”.
The Conda Cheat Sheet gives as an example:
| Constraint type | Specification | Result |
|---|---|---|
| Fuzzy | numpy=1.11 |
1.11.0, 1.11.1, 1.11.2, 1.11.18 etc. |
| Exact | numpy==1.11 |
1.11.0 |
Similarly, as pointed out by @FlyingTeller, the section Conda Package Specification (subsection Command Line Match Spec Examples) of the conda documentation gives the following examples:
| Example | Meaning |
|---|---|
conda install numpy=1.11 |
The fuzzy constraint numpy=1.11 matches 1.11, 1.11.0, 1.11.1, 1.11.2, 1.11.18, and so on. |
conda install numpy==1.11 |
The exact constraint numpy==1.11 matches 1.11, 1.11.0, 1.11.0.0, and so on. |
Arguably, this could be better documented with the commands themselves, such as conda create and conda install, where, at the time of writing, no such documentation can be found.
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