Module 9
Quality scores conceptually
From characters to meaning.
Reading quality
Each quality character encodes a number. The character 'I' corresponds to a quality score of 40, which is high confidence. Lower characters mean lower confidence.
Python
quality = "IIII"
print(ord("I") - 33)→ 40
The formula ord(char) - 33 converts a quality character to its numeric score. This is called Phred+33 encoding.