PHP Manual
Function Reference
Variable and Type Related Extensions
Data Structures
Stack
Ds\Stack::allocate
Ds\Stack::capacity
Ds\Stack::clear
Ds\Stack::__construct
Ds\Stack::copy
Ds\Stack::count
Ds\Stack::isEmpty
Ds\Stack::jsonSerialize
Ds\Stack::peek
Ds\Stack::pop
Ds\Stack::push
Ds\Stack::toArray

Ds\Stack::isEmpty

Ds\Stack::count

Returns the number of values in the stack.

See Countable::count