In this article, we will discuss different ways to check if a string starts with an alphabet or not in Python.
Table Of Contents
Check if String starts with a Letter using Regex
The regex module of Python provides a function regex.search(pattern, string). It accepts a regex pattern and a string as arguments. Then it scans through the string and look for a match to the given regex pattern. If a match is found, then it returns a Match object, otherwise, it returns None.
We will use this function and check if a string starts with an alphabet (either uppercase or lowercase). For this, we will use the regex pattern “^[a-zA-Z]”. This pattern checks that the string must only start with an uppercase or lowercase alphabet. For example,
Example 1:
import re
sample_str = "sample string"
# Check if string starts with a letter
if re.search("^[a-zA-Z]", sample_str) is not None:
print("The String starts with a letter")
else:
print("The String do not starts with a letter")
Output:
The String starts with a letter
The given string started with an alphabet.
Example 2:
import re
sample_str = "55 Words"
# Check if string starts with a letter
if re.search("^[a-zA-Z]", sample_str) is not None:
print("The String starts with a letter")
else:
print("The String do not starts with a letter")
Output:
The String do not starts with a letter
It was a negative test because the given string started with a number instead of a letter.
Check if String starts with a Letter using isapha()
In Python, the string class provides a function isalpha(). It returns True if all the characters in the string are alphabetic and at least one character in the string. We can use this to check if a string starts with a letter.
Select the first character of string using the subscript operator like str[0] and then call the isalpha() on it to check if the first character is an alphabet or not. Let’s see some examples,
Example 1:
sample_str = "sample string"
# Check if string starts with a letter
if sample_str[0].isalpha():
print("The String starts with a letter")
else:
print("The String do not starts with a letter")
Output:
The String starts with a letter
The given string started with an alphabet.
Example 2:
sample_str = "55 Words"
# Check if string starts with a letter
if sample_str[0].isalpha():
print("The String starts with a letter")
else:
print("The String do not starts with a letter")
Output:
The String do not starts with a letter
It was a negative test because the given string started with a number instead of a letter.
Summary:
We learned different ways to check if a string starts with an alphabet in Python.