# isYearStart {#isyearstart}

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

## Syntax {#syntax}

`isYearStart(X)`

## Arguments {#arguments}

**X** is a scalar/vector of type DATE, DATEHOUR, DATETIME, TIMESTAMP or NANOTIMESTAMP.

## Details {#details}

Determine if each element in *X* is the first day of a year.

## Examples {#examples}

```
isYearStart(2012.01.01);
// output: true

isYearStart([2012.01.01,2012.02.01]);
// output: [true,false]
```

Related function: [isYearEnd](isYearEnd.md)

