---
name: "PDL::Delta"
section: "1p"
platform: "linux"
package: "pdl"
version: "1:2.025-1"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/PDL::Delta"
---

# PDL::Delta(1p)

PDL changes between V1.0 and V2.0

## NAME

PDL::Delta - PDL changes between V1.0 and V2.0

## DESCRIPTION

This file is an attempt to list the major user-visible changes between PDL versions 1.0 and 2.0.

## Core Changes

### Piddles are not hashes any more:

```
    $x = zeroes 10,10;
    $$x{FOO} = "bar"
```

doesn't work. They are currently scalar references (to opaque C structures in finer terms) because of speed as well as syntactic issues. If you want to have a hash, use

```
    $x->hdr()
```

which returns a reference to an anonymous hash. Also, subclassing works if you store a piddle in the hash member \`\`PDL''.

There are also many core enhancements to support Dataflow and Slicing tricks, but these do not introduce any incompatibilities.

### Incompatible Changes vs 1.11

- rgrep

  Order of the arguments has changed.

- copy method

  No longer copies the header. This may not be a misfeature.

## Documentation Changes

Many of the base and library pods were updated.

## SEE ALSO

The *Changes* file for exhaustive details on what changed.

The *INSTALL* file for how to build PDL.

The *README* file for general stuff.

## HISTORY

pdldelta was inspired by *perldelta*  man page in the Perl 5.004 distribution.