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# NumPy isalpha() function

In this tutorial, we will cover `isalpha()` function of the char module in the Numpy library.

The `isalpha()` function returns True if all the characters in the string element are alphabets, otherwise, this function will return False.

This function calls `str.isalpha` internally for each element of the array.

This function is locale-dependent for an 8-bit string.

• In case if the element contains mixed characters(alphabets and digits) then this function will return False.

• If there are whitespaces in a string then also this function returns False.

### Syntax of `isalpha()`:

The syntax required to use this function is as follows:

``numpy.char.isalpha(arr)``

The above syntax indicates that `isalpha()` function takes a single parameter.

In the above syntax, the argument `arr` is mainly used to indicate the input array of strings on which this function will be applied.

Returned Values:

This function will return an output array of boolean values, with True and False values corresponding to every string element, based on whether the string is in uppercase or not.

## Example 1: With an array of strings

Let's take the first example with an array of strings:

``````import numpy as np

inp_ar = np.array([ 'Ram', 'Mohan', 'Apple9','Chair s'] )
print("The Input string is:")
print(inp_ar)

x = np.char.isalpha(inp_ar)
print("The Output is:")
print(x)``````

The Input string is:
['Ram' 'Mohan' 'Apple9' 'Chair s']
The Output is:
[ True True False False]

## Example 2: With an array of alpha-numeric values

In the below code snippet, we will use `isalpha()` function with alpha-numeric values in an array:

``````import numpy as np

inp_ar = np.array([ 'Superb !', 'Amazing!', 'fab','cool123'] )
print("The Input string is:")
print(inp_ar)

x = np.char.isalpha(inp_ar)
print("The Output is:")
print(x)``````

The Input string is:
['Superb !' 'Amazing!' 'fab' 'cool123']
The Output is:
[False False True False]

## Summary

In this tutorial we learned about `isalpha()` function of the Numpy library. We covered how it is used with its syntax and values returned by this function with some code examples.