Conda - Get list of package starting with certain letter(s)

Conda List Command

The conda list command is sufficiently expressive to do this. Specifically, examining the usage signature for the command shows that it accepts a regex argument:

$ conda list -h
usage: conda list [-h] [-n ENVIRONMENT | -p PATH] [--json] [-v] [-q]
                  [--show-channel-urls] [-c] [-f] [--explicit] [--md5] [-e]
                  [-r] [--no-pip]
                  [regex]

List linked packages in a conda environment.

Options:

positional arguments:
  regex                 List only packages matching this regular expression.
...

Examples

Here are some examples using a regular expression to find packages starting with specific strings.

Packages starting with "sci"

$ conda list '^sci'
# packages in environment at /Users/merv/miniconda3/envs/anaconda_2020_11:
#
# Name                    Version                   Build  Channel
scikit-image              0.17.2           py38h81aa140_0  
scikit-learn              0.23.2           py38h959d312_0  
scipy                     1.5.2            py38h2515648_0  

Packages starting with "num" or "sci"

$ conda list '^(sci|num)'
# packages in environment at /Users/merv/miniconda3/envs/anaconda_2020_11:
#
# Name                    Version                   Build  Channel
numba                     0.51.2           py38h6440ff4_1  
numexpr                   2.7.1            py38hce01a72_0  
numpy                     1.19.2           py38h456fd55_0  
numpy-base                1.19.2           py38hcfb5961_0  
numpydoc                  1.1.0              pyhd3eb1b0_1  
scikit-image              0.17.2           py38h81aa140_0  
scikit-learn              0.23.2           py38h959d312_0  
scipy                     1.5.2            py38h2515648_0

This should be preferred over using grep because it will preserve the header that conda list outputs.