nushell/docs/commands/histogram.md

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# histogram
Creates a new table with a histogram based on the column name passed in.
Syntax: `histogram <column_name> ...args`
## Parameters
* `<column-name>`: name of the column to graph by
* `args`: column name to give the histogram's frequency column
## Examples
Let's say we have this file `random_numers.csv` which contains 50 random numbers.
**Note**: The input doesn't have to be numbers it works on strings too. Try it out.
```shell
> open random_numbers.csv
────┬────────────────
# │ random numbers
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────┼────────────────
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0 │ 5
1 │ 2
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2 │ 0
...
2020-08-15 07:31:17 +02:00
47 │ 1
48 │ 1
49 │ 2
────┴────────────────
```
If we now want to see how often the different numbers were generated, we can use the `histogram` function:
```shell
> open random_numbers.csv | histogram "random numbers"
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───┬────────────────┬─────────────┬────────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────
# │ random numbers │ occurrences │ percentage │ frequency
───┼────────────────┼─────────────┼────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────
0 │ 0 │ 8 │ 57.14% │ *********************************************************
1 │ 1 │ 14 │ 100.00% │ ****************************************************************************************************
2 │ 2 │ 9 │ 64.29% │ ****************************************************************
3 │ 3 │ 6 │ 42.86% │ ******************************************
4 │ 4 │ 3 │ 21.43% │ *********************
5 │ 5 │ 10 │ 71.43% │ ***********************************************************************
───┴────────────────┴─────────────┴────────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────
```
We can also set the name of the second column or sort the table:
```shell
> open random_numbers.csv | histogram "random numbers" probability
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───┬────────────────┬─────────────┬────────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────
# │ random numbers │ occurrences │ percentage │ probability
───┼────────────────┼─────────────┼────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────
0 │ 0 │ 8 │ 57.14% │ *********************************************************
1 │ 1 │ 14 │ 100.00% │ ****************************************************************************************************
2 │ 2 │ 9 │ 64.29% │ ****************************************************************
3 │ 3 │ 6 │ 42.86% │ ******************************************
4 │ 4 │ 3 │ 21.43% │ *********************
5 │ 5 │ 10 │ 71.43% │ ***********************************************************************
───┴────────────────┴─────────────┴────────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────
2019-11-28 19:32:31 +01:00
```
```shell
> open random_numbers.csv | histogram "random numbers" probability | sort-by probability
2020-08-15 07:31:17 +02:00
───┬────────────────┬─────────────┬────────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────
# │ random numbers │ occurrences │ percentage │ probability
───┼────────────────┼─────────────┼────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────
0 │ 4 │ 3 │ 21.43% │ *********************
1 │ 3 │ 6 │ 42.86% │ ******************************************
2 │ 0 │ 8 │ 57.14% │ *********************************************************
3 │ 2 │ 9 │ 64.29% │ ****************************************************************
4 │ 5 │ 10 │ 71.43% │ ***********************************************************************
5 │ 1 │ 14 │ 100.00% │ ****************************************************************************************************
───┴────────────────┴─────────────┴────────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────
```
Of course, histogram operations are not restricted to just analyzing numbers in files, you can also analyze your directories
```shell
2020-08-15 07:31:17 +02:00
> ls -la | histogram type | sort-by occurrences
───┬─────────┬─────────────┬────────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────
# │ type │ occurrences │ percentage │ frequency
───┼─────────┼─────────────┼────────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────
0 │ Dir │ 5 │ 4.76% │ ****
1 │ Symlink │ 28 │ 26.67% │ **************************
2 │ File │ 105 │ 100.00% │ ****************************************************************************************************
───┴─────────┴─────────────┴────────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────
```