====== How-to filter proteins or protein groups ======

On a [[userguide:contextdefinition| User Context]] it is possible to apply filters. Filter will mark as //hidden// (or //masked//) protein groups or proteins inside protein groups (depending on user choice) according user defined criteria. 

  * If protein groups are filtered (i.e. "Apply to proteins" is NOT checked), the typical protein is considered but the whole group is (eventually) marked as //hidden//. 
  * If proteins are filtered (i.e. "Apply to proteins" is checked), each protein from every protein groups are considered and (eventually) marked as //hidden//. If a typical protein is //hidden//, then another sameset protein become the typical protein. If there is no more //visible// sameset protein then the whole protein group is set as //hidden//.

The available filters are described in the how-to [[how_to:proteinfiltering|filter proteins [groups] ]]. 

If several filters are applied successively, the previous filter(s) is(are) not reset ("cumulative" effect).

===== Impact of masking proteins [groups] in algorithms  =====

Once a protein or a protein groups is masked, it will be taken into account is some operations.

==== Masked protein groups ====

In visualization, 
  * masked protein groups will be identified in navigation (see [[userguide:proteingroups|context protein groups]]). 
  * in [[how_to:peptideview|peptides list]], peptides referenced by only hidden protein groups will be identified in the same way.

The export operations (for AMT or reports) will only export valid (none masked) protein groups. This is also the case for ''Contexts comparison'' algorithm. 

__**The other algorithms (change master / spectral count / protein grouping (peptide to consider) are not impacted and (even if not necessary), they could be applied to all protein groups.**__
==== Masked proteins====

If user choose to apply filter on individual proteins, valid protein groups may contains valid and masked proteins. 

In visualization, the [[userguide:proteingroups|protein group view]] identify //masked// proteins in sameset and/or subset lists. 

For the export :
  * only  valid (none masked) protein are considered when exporting to AMT db.
  * for reports, only one report is impacted (same subset detail report) and for each protein in valid protein groups, the masked property is indicated.

  * The ''Contexts comparison'' algorithm is impacted in the same way as when protein groups are masked : only valid proteins should be considered. 
  * ''Change typical protein'' operation does not select //masked// protein as typical !

__**The other algorithms (spectral count / grouping (peptide to consider) are not impacted.**__