# countGraphs -- counts the number of graphs in the list with given properties

## Synopsis

• Usage:
n = countGraphs(L, s)
n = countGraphs(L, h)
n = countGraphs(L, l)
• Inputs:
• Outputs:
• n, an integer, the number of graphs in $L$ satisfying the filter

## Description

Counts the number of graphs in a list that satisfy certain restraints as given in the filter (see buildGraphFilter). Notice that the input list can be graphs represented as instances of the class Graph or in a nauty-based String format.

For example, we can count the number of connected graphs on five vertices.

 i1 : L = generateGraphs 5; i2 : countGraphs(L, {"Connectivity" => 0, "NegateConnectivity" => true}) o2 = 21