Count Lines

数行

≈ 15 min · python-file-io python-loops · Open in WolfCode

One line of body. The lesson is the choice between sum(1 for _ in f) and the explicit loop.

Python · runnable

# Setup
with open("notes.txt", "w") as f:
    f.write("hello\n\nworld\n   \npython\n")

def total_lines(path):
    with open(path) as f:
        return sum(1 for _ in f)

def non_empty_lines(path):
    with open(path) as f:
        return sum(1 for line in f if line.strip())

print("total    :", total_lines("notes.txt"))
print("non-empty:", non_empty_lines("notes.txt"))

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