Overview
This lecture explains how to reverse a string in Python and create a simple program to check if a user's input is a palindrome.
Reversing a String in Python
- Python does not have a built-in string reverse method.
- String slicing extracts characters by specifying start, finish, and step inside square brackets.
- Leaving start and finish blank with step -1 (i.e.,
[::-1]) reverses the string.
Palindrome Program Steps
- Prompt the user to input a string and store it in a variable (e.g.,
original).
- Reverse the string using slicing and store it in another variable (e.g.,
reverse).
- Use an if statement to compare the original and reversed strings.
- If both strings are equal, print that the string is a palindrome; otherwise, print that it is not.
Program Example
- User input is taken and reversed.
- Conditional logic checks for palindrome status.
- Program can be run multiple times for different inputs.
Recap of the Process
- Obtain user input as the original string.
- Reverse the string using slicing.
- Use a conditional statement to compare and print the result.
Key Terms & Definitions
- Palindrome — a sequence of characters that reads the same forwards and backwards.
- Slicing — extracting parts of a string using start, finish, and step parameters:
[start:finish:step].
Action Items / Next Steps
- Practice writing the palindrome checker program using string slicing and if statements.
- Test the program with various inputs to confirm correctness.