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Python – Check If String Starts with a Vowel

In this tutorial, we will look at how to check if a string in Python starts with a vowel or not with the help of some examples.

How to check if a string starts with a vowel character?

check if string starts with a vowel in python

To check if a string in Python starts with a vowel or not, check if the first character in the string is a vowel using the membership operator in.

The membership operator in in Python, returns True if a value is in a collection (for example, a character is present in a string) and returns False otherwise.

So, use the membership operator in to check if the first character in the string (character at index 0) is one of the vowel characters or not. The following is the syntax –

# check if string starts with a vowel
s[0].lower() in "aeiou"

Here, we use the string lower() function to make the vowel check case-insensitive. It returns True if the string starts with a vowel.

Examples

Let’s now look at some examples. First, we will create some strings that we will use throughout this tutorial.

# create strings
s1 = "apple"
s2 = "banana"
s3 = "$500"
s4 = ""

# display the strings
print(s1)
print(s2)
print(s3)
print(s4)

Output:

apple
banana
$500

Here, we created four strings – s1, s2, s3 and s4. The string s1 starts with a vowel, the string s2 does not start with a vowel, the string s3 starts with the special character '$' and the string s4 is an empty string.

Let’s now check if the strings s1, s2, and s3 start with a vowel or not.

# check if string starts wtih a vowel
print(s1[0].lower() in "aeiou")
print(s2[0].lower() in "aeiou")
print(s3[0].lower() in "aeiou")

Output:

True
False
False

We get True for s1 as it does start with a vowel. We get False for s2 and s3 as they do not start with a vowel.

Now let’s apply the above method to the empty string, s4.

# check if string starts wtih a vowel
print(s4[0].lower() in "aeiou")

Output:

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
Input In [3], in <module>
      1 # check if string starts wtih a vowel
----> 2 print(s4[0].lower() in "aeiou")

IndexError: string index out of range

We get an IndexError because we’re trying to access an index that does not exist (an empty string does not have a 0 index).

To avoid the above error, you can first check whether the string is non-empty and then proceed to check if the first character is a vowel or not. See the example below –

# function to check if string starts with a vowel
def check_str_starts_with_vowel(s):
    if s and s[0].lower() in "aeiou":
        return True
    else:
        return False

# check if string starts with a vowel
print(check_str_starts_with_vowel(s4))

Output:

False

We get False as the output for the empty string.

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Author

  • Piyush

    Piyush is a data scientist passionate about using data to understand things better and make informed decisions. In the past, he's worked as a Data Scientist for ZS and holds an engineering degree from IIT Roorkee. His hobbies include watching cricket, reading, and working on side projects.