# Preprocessing: `pp`

Functions for loading VCF files, annotating variants, and filtering.

## Loading data

```{eval-rst}
.. module:: cellspec.pp
.. currentmodule:: cellspec

.. autosummary::
    :toctree: ../generated

    pp.load_vcf
```

## Annotation

```{eval-rst}
.. autosummary::
    :toctree: ../generated

    pp.annotate_contexts
    pp.add_vaf_layer
```

## Filtering

```{eval-rst}
.. autosummary::
    :toctree: ../generated

    pp.filter_variants
    pp.filter_cells
    pp.filter_by_coverage
    pp.filter_to_snps
```