GC Content Counter

A simple Python script to calculate the GC content of a DNA sequence. The program validates the DNA sequence input and calculates the number of G and C bases, the total GC content, and the GC percentage. Features :

• Validates DNA sequences to ensure only A, T, G, and C are entered.
• Counts the number of G and C bases.
• Calculates total GC content and GC percentage.
• Interactive and user-friendly input prompt.

Development Process:

Here’s how I developed this project through multiple attempts and what I learned from each:

Initiative 1: Built a basic GC content calculator. Learnings: Taking input, looping through input, performing calculations, using built-in count() function.

Initiative 2: Realized that user input may contain invalid letters, so input validation is needed. Learnings: Looping through input, using not in to check invalid characters.

Initiative 3: Detected that initial validation only checked letters individually but didn’t handle sequences containing extra invalid characters. Learnings: Applied a while loop to repeatedly ask for input until it is fully valid.

Initiative 4: Improved feedback to the user to make errors more observable in their input. Learnings: Used formatted strings (f'') for clearer messages.

Requirements

• Python 3.x

Usage

Clone the repository:

git clone https://github.com/Joyeeta007/GC_Content_Counter.git
cd GC_Content_Counter
python GC_Content_Counter.py

Enter your DNA sequence when prompted. The program will validate your input and calculate the GC content.

Example Output:

Enter DNA Sequence: ATGCGCAT C count: 3

G count: 3

GC sum: 6

Sequence length: 8

GC Content: 75.00%