# datefind

Indices of dates in matrix

## Syntax

``Indices = datefind(Subset,Superset)``
``Indices = datefind(___,Tolerance)``

## Description

````Indices = datefind(Subset,Superset)` returns a vector of indices to the date numbers in `Superset` that are present in `Subset`. If no date numbers match, ```Indices = []```.```

````Indices = datefind(___,Tolerance)` returns a vector of indices to the date numbers in `Superset` that are present in `Subset`, plus the optional argument for `Tolerance`. If no date numbers match, ```Indices = []```.```

## Examples

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This example shows how to return a vector of indices to date numbers.

```Superset = datenum(1999, 7, 1:31); Subset = [datenum(1999, 7, 10); datenum(1999, 7, 20)]; Indices = datefind(Subset, Superset, 1)```
```Indices = 6×1 9 10 11 19 20 21 ```

## Input Arguments

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Subset of dates to find matching dates in `Superset`, specified as a matrix of nonnegative integers with values for serial date numbers or datetime arrays.

`Subset` and `Superset` can be either serial date numbers or datetime arrays. These types do not have to match. `datefind` determines the underlying date to match dates of different data types.

Note

The elements of `Subset` must be contained in `Superset`, without repetition. `datefind` works with non-repeating sequences of dates.

Example: `Subset = [datenum(1997,7,10); datenum(1997,7,20)];`

Data Types: `single` | `double`

Superset of dates, specified as a matrix of serial date numbers or datetime arrays, whose elements are sought.

`Subset` and `Superset` can be either serial date numbers or datetime arrays. These types do not have to match. `datefind` determines the underlying date to match dates of different data types.

Note

The elements of `Subset` must be contained in `Superset`, without repetition. `datefind` works with non-repeating sequences of dates.

Example: `Superset = datenum(1997,7,1:31);`

Data Types: `single` | `double`

Tolerance for matching dates (`+/-`) in `Superset`, specified as a positive integer or duration object.

Data Types: `single` | `double`

## Output Arguments

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Indices of dates in `Superset` that are present in `Subset` (plus or minus the tolerance if defined using the optional argument `Tolerance`), returned as a vector of indices to the date numbers or datetimes.