# isIndexedSeries {#isindexedseries}

**Parent topic:**[Functions](../../Functions/category.md)

## Syntax {#syntax}

`isIndexedSeries(X)`

## Arguments {#arguments}

**X** is a matrix with only 1 column.

## Details {#details}

Determine if *X* is an indexed series.

## Examples {#examples}

```
s=matrix(1..10).rename!(2020.01.01..2020.01.10, );

isIndexedSeries(s);
// output: false

s.setIndexedSeries!()
isIndexedSeries(s);
// output: true
```

