---
name: keys
status: documented
runtime: pp
source: src/runtime/pp/aggregate.rs
---
```{index} single: keys; Perl built-in (pp runtime)
```

# keys

## Synopsis

```perl
my @k = keys %hash;
my $count = keys %hash;         # scalar context: number of keys
for my $key (keys %hash) { ... }
```

## Description

Returns all keys of a hash, or the number of keys in scalar context.

In list context, pushes all keys of the hash onto the stack as
individual string values. In scalar context, returns the number of
key-value pairs. Accepts both `%hash` and `$hashref` (auto-
dereferences). As a side effect, resets the hash's internal
iterator used by `each`.

## See also

values, each, exists, delete