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```{index} single: Scalar::Util::Numeric
```

# Scalar::Util::Numeric

```{pperl-module-badges} Scalar::Util::Numeric
```

Numeric tests for scalars: is a value a number, and what kind.

Each function asks perl's own number parser (`grok_number`, the one
`looks_like_number` uses) about the string form of its argument, so a
string and a number answer alike: `isint("42")` and `isint(42)` are
both true.


## Synopsis

```perl
use Scalar::Util::Numeric qw(isnum isint isfloat isneg);

print isnum("3.5e2") ? "number\n" : "not\n";   # number
print isint(" 7 "), "\n";                      # 1
print isint("-7"), "\n";                       # -1
print isfloat("1e3"), "\n";                    # 1
print isnum("abc"), "\n";                      # 0
```

## Functions

`isnum($v)` is `grok_number`'s answer: 0 for a non-number, otherwise
a set of flags - 0x01 the value fits a UV, 0x02 it is larger, 0x04 it
has a fraction or an exponent, 0x08 it is negative, 0x10 infinity,
0x20 NaN. `isint` is 1 for a non-negative integer, -1 for a negative
one and 0 otherwise; `isuv`, `isbig`, `isfloat`, `isneg`, `isinf` and
`isnan` each test one flag and return 1 or 0. `uvmax()` is the largest
UV. `undef` is not a number. Nothing is exported by default; `:all`
exports the eight tests.

This is a native implementation of Scalar::Util::Numeric 0.40's
`Numeric.xs`; its `Scalar/Util/Numeric.pm` is used unchanged.

## Differences from upstream

None.

## Functions

### Numeric tests

#### `uvmax`

The largest unsigned integer perl holds natively.

**Synopsis**

```perl
my $max = Scalar::Util::Numeric::uvmax();   # 18446744073709551615
```

#### [`isnum`](Numeric/isnum)

Whether a value is a number, and which kind.

#### [`isint`](Numeric/isint)

Whether a value is an integer, and its sign.

#### [`isuv`](Numeric/isuv)

Whether a value is a number that fits an unsigned integer.

#### [`isbig`](Numeric/isbig)

Whether a value is a number larger than the unsigned range.

#### [`isfloat`](Numeric/isfloat)

Whether a value is a number with a fraction or an exponent.

#### `isneg`

Whether a value is a negative number.

**Synopsis**

```perl
use Scalar::Util::Numeric qw(isneg);
isneg("-3");   # 1
```

**What you get back**

1 when the number has a leading minus sign, else 0.

#### [`isinf`](Numeric/isinf)

Whether a value is infinity.

#### `isnan`

Whether a value is NaN.

**Synopsis**

```perl
use Scalar::Util::Numeric qw(isnan);
isnan("NaN");   # 1
```

**What you get back**

1 for a NaN, in any spelling perl reads as NaN, else 0.

```{toctree}
:hidden:
:maxdepth: 1

Numeric/isnum
Numeric/isint
Numeric/isuv
Numeric/isbig
Numeric/isfloat
Numeric/isinf
```