Conda notes

From raju

replicate environment

Method 1

Check the environments installed

    conda info --envs

Export the environment

    conda env export --name FOO | grep -v "^prefix: " > environment.yml

Note: By default, the output of "conda env export" contains a line

    prefix: /path/to/the/environment

This line is not necessary in order to recreate the environment. Grepping it out so that the replicating user will not know what the original environment's path is.

Another way

  • On Windows
    activate myenv
    conda env export | grep -v "^prefix: " > environment.yml
  • On Linux
    source activate myenv
    conda env export | grep -v "^prefix: " > environment.yml
    source deactivate

To recreate it

    conda env create -f environment.yml
    activate myenv


Method 2

Get the list of packages

    $ conda list --export --name old_environment > req.txt


    $ conda list -e -n old_environment > req.txt

Create a new environment using

    $ conda create -n new_environment --file req.txt


List all the environments

    conda info --envs

clone an environment

tags | copy environment

    conda create --name new_environment --clone old_environment


Create an environment

Always specify the python version you want while creating the environment. For example

    conda create --name foo python=2.7

If python version is not specified, there will not be a python.exe under the corresponding environment directory /c/ProgramData/Continuum/Anaconda/envs/foo . The python.exe is needed to link this environment in pycharm when choosing the python interpreter path.

Sample commands used in the past

    conda create -n market_data_processor python=3.6 pandas pep8 pandas-datareader

Create an environment for python 3.6

    conda create -n py36 python=3.6 anaconda

Switch to the new environment

    activate py36

Remove an environment

    conda env remove --name foo

tags | delete

list current environment

Use $CONDA_DEFAULT_ENV to get the current environment name. For example

    $ source activate py36

This is useful to activate a conda environment if it is not the current environment. See for example

install a specific version of a package in an environment

    conda install -n <env> <package>=<version>

For example

    conda install -n py27 pandas=0.19.2

find the package version

To find the version of the package installed

    conda list -n env_name package_name

For example

    conda list -n foo pandas

You can use this technique to check if a package is installed.

Other related commands

  • conda list - list all packages in the current environment


path to python

The python used by an activated conda environment is ${CONDA_PREFIX}/bin/python

activate a conda environement if it is not already activated

    # desired environment is set to py36. Change it as needed.
    if [[ $current_env != $desired_env ]];
        echo "setting environment to $desired_env"
        source activate $desired_env

In action |

specify minimum version in the environment file -> pg-2 -> "Specifying version numbers" section

update environment

    conda env update -f FILE

where FILE is the path of the environment file


sample environment file

    name: py36
      - anaconda-fusion
      - defaults
      - python=3.6

useful links

file locations

  • pep8 - /c/ProgramData/Anaconda3/Scripts/pep8.exe
  • python interpreter - /c/ProgramData/Anaconda3/python