<!-- GENERATED by docs/sphinx/bin/02-reference from PDL/Bad.rs. Do not edit. -->

```{index} single: PDL::Bad; Perl module
```

# PDL::Bad

```{pperl-module-badges} PDL::Bad
```

##  Synopsis

    use PDL;
    my $a = pdl [1, 2, 3];
    $a->badflag(1);
    $a->set(1, $a->badvalue);
    print $a->nbad, "\n";      # 1
    print $a->ngood, "\n";     # 2

## Functions

### Other Functions

#### `setvaltobad`

`setvaltobad($pdl, $val)` — set elements equal to `$val` as bad. Upstream `Bad.pd:625`. Same signature as setbadtoval: `pdl_run_setvaltobad(a, b, value)`. Engine restored 2026-04-19. Honours `PDL_INPLACE` so `$x->inplace->setvaltobad(1)` mutates `$x`.

#### `setbadtoval`

`setbadtoval($pdl, $val)` — replace bad values with `$val`.

#### `badmask`

`badmask($pdl, $replacement)` — replace bad values with `$replacement`.

#### `setbadat`

`setbadat($pdl, @indices)` — set element at given indices to the bad value and enable the badflag.

#### `setinftobad`

`setinftobad($pdl)` — set Inf/-Inf elements to bad value, enable badflag. Returns a new pdl (or modifies inplace if inplace flag set).

#### `setnonfinitetobad`

`setnonfinitetobad($pdl)` — set NaN and Inf/-Inf elements to bad value, enable badflag. Returns a new pdl (or modifies inplace if inplace flag set). Combines setnantobad and setinftobad behavior.

#### `isfinite`

`isfinite($pdl)` — returns a PDL of 1s for finite values, 0s for NaN/Inf/bad. Mirrors `PDL::Bad::isfinite`.