When it is required to check if a string starts with a specific substring or not, with the help of regular expression, a method is defined that iterates through the string and uses the ‘search’ method to check if a string begins with a specific substring or not.
Example
Below is a demonstration of the same
import re def check_string(my_string, sub_string) : if (sub_string in my_string): concat_string = "^" + sub_string result = re.search(concat_string, my_string) if result : print("The string starts with the given substring") else : print("The string doesnot start with the given substring") else : print("It is not a substring") my_string = "Python coding is fun to learn" sub_string = "Python" print("The string is :") print(my_string) print("The sub-string is :") print(sub_string) check_string(my_string, sub_string)
Output
The string is : Python coding is fun to learn The sub-string is : Python The string starts with the given substring
Explanation
The required packages are imported.
A method named ‘check_string’ is defined that takes the string and a substring as parameter.
It iterates through the string, and concatenates the ‘^’ with the substring.
This is assigned to a new variable.
The ‘search’ method is used to check for the substring in the new variable.
The result is assigned to a variable.
If this is result is a true value, relevant output is displayed on the console.
Outside the console, a string is defined, and is displayed on the console.
A substring is defined and is displayed on the console.
The method is called by passing the string and the substring.
The output is displayed on the console.