Files & Errors

Reading, writing, and exception handling.

01Write and read a file

main.py

with open("note.txt", "w") as f:
    f.write("hello\nworld\n")

with open("note.txt") as f:
    print(f.read())

Output

hello
world

main.py

try:
    n = int("abc")
except ValueError as e:
    print("Caught:", e)

Output

Caught: invalid literal for int() with base 10: 'abc'

main.py

try:
    x = 10 / 0
except ZeroDivisionError:
    print("Cannot divide by zero")
finally:
    print("Done")

Output

Cannot divide by zero
Done

main.py

def sqrt(n):
    if n < 0:
        raise ValueError("n must be >= 0")
    return n ** 0.5

try:
    sqrt(-1)
except ValueError as e:
    print(e)

Output

n must be >= 0