print is Python’s built-in way to output a message or value to the screen. It is the output counterpart to input, which receives information from the keyboard. section 4.3.1
Use print to:
- Show text or computed values, such as a greeting or the area of a square. section 2.6.1
- Inspect variable values while debugging, placing statements at useful points in a function or loop. section 8.2.1
- Trace which values cause an incorrect result, such as identifying every word counted by a matching loop. section 8.2.1
Finding an overcount
A word-counting function that checks whether "dan" appears anywhere counts both "Dan" and "danger". Add print(word, "is being counted") inside the if statement, rerun the test, and inspect the output. The trace reveals which word causes the unexpected count, helping guide a correction that counts only the exact word "Dan". section 8.2.1
Listing 8.2 Example of a print statement to find the bug
def count_words(words):
count = 0
for word in words:
if "dan" in word.lower():
print(word,"is being counted") #1
count += 1
return count
View the debugging listing that places print at the point where the counter changes. section 8.2.1
