# isletter

Determine which characters are letters.

## 📝 Syntax

* res = isletter(str)

## 📥 Input argument

* str - scalar, vector, matrix or multidimensional array.

## 📤 Output argument

* res - logical array

## 📄 Description

isletter determines which characters are letters.

## 💡 Examples

```matlab
isletter('Nel Son')
```

```matlab
isletter("六書 six writings")
```

## 🔗 See also

[toupper](https://nelson-9.gitbook.io/nelson/markdown/en/string/toupper).

## 🕔 History

| Version | 📄 Description  |
| ------- | --------------- |
| 1.0.0   | initial version |


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