---
title: experimental.histogram() function
description: >
  `experimental.histogram()` approximates the cumulative distribution of a dataset by counting
  data frequencies for a list of bins.
menu:
  flux_v0_ref:
    name: experimental.histogram
    parent: experimental
    identifier: experimental/histogram
weight: 101
flux/v0/tags: [transformations]
introduced: 0.112.0
---

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`experimental.histogram()` approximates the cumulative distribution of a dataset by counting
data frequencies for a list of bins.

A bin is defined by an upper bound where all data points that are less than
or equal to the bound are counted in the bin.
Bin counts are cumulative.

#### Function behavior
- Outputs a single table for each input table.
- Each output table represents a unique histogram.
- Output tables have the same group key as the corresponding input table.
- Drops columns that are not part of the group key.
- Adds an `le` column to store upper bound values.
- Stores bin counts in the `_value` column.

##### Function type signature

```js
(<-tables: stream[{A with _value: float}], bins: [float], ?normalize: bool) => stream[{A with le: float, _value: float}]
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### bins
({{< req >}})
List of upper bounds to use when computing histogram frequencies,
including the maximum value of the data set.

This value can be set to positive infinity (`float(v: "+Inf")`) if no maximum is known.
##### Bin helper functions
The following helper functions can be used to generated bins.
- `linearBins()`
- `logarithmicBins()`

### normalize

Convert count values into frequency values between 0 and 1.
Default is `false`.

**Note**: Normalized histograms cannot be aggregated by summing their counts.

### tables

Input data. Default is piped-forward data (`<-`).




## Examples

### Create a histogram from input data

```js
import "experimental"
import "sampledata"

sampledata.float()
    |> experimental.histogram(
        bins: [
            0.0,
            5.0,
            10.0,
            15.0,
            20.0,
        ],
    )

```

{{< expand-wrapper >}}
{{% expand "View example input and output" %}}

#### Input data

| _time                | *tag | _value  |
| -------------------- | ---- | ------- |
| 2021-01-01T00:00:00Z | t1   | -2.18   |
| 2021-01-01T00:00:10Z | t1   | 10.92   |
| 2021-01-01T00:00:20Z | t1   | 7.35    |
| 2021-01-01T00:00:30Z | t1   | 17.53   |
| 2021-01-01T00:00:40Z | t1   | 15.23   |
| 2021-01-01T00:00:50Z | t1   | 4.43    |

| _time                | *tag | _value  |
| -------------------- | ---- | ------- |
| 2021-01-01T00:00:00Z | t2   | 19.85   |
| 2021-01-01T00:00:10Z | t2   | 4.97    |
| 2021-01-01T00:00:20Z | t2   | -3.75   |
| 2021-01-01T00:00:30Z | t2   | 19.77   |
| 2021-01-01T00:00:40Z | t2   | 13.86   |
| 2021-01-01T00:00:50Z | t2   | 1.86    |


#### Output data

| *tag | le  | _value  |
| ---- | --- | ------- |
| t1   | 0   | 1       |
| t1   | 5   | 2       |
| t1   | 10  | 3       |
| t1   | 15  | 4       |
| t1   | 20  | 6       |

| *tag | le  | _value  |
| ---- | --- | ------- |
| t2   | 0   | 1       |
| t2   | 5   | 3       |
| t2   | 10  | 3       |
| t2   | 15  | 4       |
| t2   | 20  | 6       |

{{% /expand %}}
{{< /expand-wrapper >}}