# daysact

Actual number of days between dates

## Syntax

``NumDays = daysact(StartDate)``
``NumDays = daysact(___,EndDate)``

## Description

example

````NumDays = daysact(StartDate)` returns the actual number of days between the MATLAB® base date and `StartDate`. In MATLAB, the base date `1` is 1-Jan-0000 A.D. See `datenum` for a similar function.```

example

````NumDays = daysact(___,EndDate)` returns the actual number of days between `StartDate` and the optional argument `EndDate`.If `EndDate` is earlier than `StartDate`, `NumDays` is negative. Under this convention, all months contain 30 days.Either input argument can contain multiple values, but if so, the other must contain the same number of values or a single value that applies to all. For example, if `StartDate` is an n-row character array of date character vectors, then `EndDate` must be an `N`-by-`1` vector of integers or a single integer. `NumDays` is then an `N`-by-`1` vector of date numbers. ```

## Examples

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Determine the `NumDays` using date character vectors for `StartDate` and `EndDate`.

`NumDays = daysact('7-sep-2002', '25-dec-2002')`
```NumDays = 109 ```

Determine the `NumDays` using a datetime array for `StartDate`.

`NumDays = daysact(datetime('7-sep-2002','Locale','en_US'), '25-dec-2002')`
```NumDays = 109 ```

Determine the `NumDays` using a vector for `EndDate`.

```MoreDays = ['09/07/2002'; '10/22/2002'; '11/05/2002']; NumDays = daysact(MoreDays, '12/25/2002')```
```NumDays = 3×1 109 64 50 ```

## Input Arguments

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Start date, specified as a scalar or an `N`-by-`1` or `1`-by-`N` vector using serial date numbers, date character vectors, or datetime arrays.

Data Types: `double` | `char` | `datetime`

End date, specified as a scalar or an `N`-by-`1` or `1`-by-`N` vector using serial date numbers, date character vectors, or datetime arrays.

Data Types: `double` | `char` | `datetime`

## Output Arguments

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Number of days between two dates based on the actual number of days, returned as a scalar or an `N`-by-`1` or `1`-by-`N` vector containing the number of days.

`NumDays` returns as a double for serial date number, date character vector, or datetime inputs for `StartDate` and `EndDate`.

## References

[1] Addendum to Securities Industry Association, Standard Securities Calculation Methods: Fixed Income Securities Formulas for Analytic Measures. Vol. 2, Spring 1995.