try / except / else / finally

مقدمة

try/except الأساسية

try:
    x = int('abc')
except ValueError:
    print('not a number')

التقاط كائن الاستثناء

try:
    int('oops')
except ValueError as e:
    print(f'Error: {e}')

التقاط استثناءات متعددة

for val in ['abc', None, 42]:
    try:
        print(int(val))
    except (TypeError, ValueError) as e:
        print(f'skipping {val!r}: {e}')

except المجردة (تجنبها)

try:
    risky = 1/0
except ZeroDivisionError:
    print('division error')  # specific

عبارات except متعددة

def process(val):
    try:
        return 10 / int(val)
    except ValueError:
        print('not a number')
    except ZeroDivisionError:
        print('division by zero')
process('abc')
process('0')

عبارة else

try:
    x = int('42')
except ValueError:
    print('bad input')
else:
    print('parsed:', x)

عبارة finally

def read_file(path):
    f = None
    try:
        f = open(path)
        return f.read()
    except FileNotFoundError:
        return None
    finally:
        if f: f.close()
print(read_file('/nonexistent'))

finally مع return

def demo():
    try:
        return 'try'
    finally:
        return 'finally'  # overrides!
print(demo())

كتل try متداخلة

try:
    try:
        x = 1/0
    except ValueError:
        print('inner')
except ZeroDivisionError:
    print('outer caught it')

تسجيل الاستثناءات

import logging
try:
    1/0
except ZeroDivisionError:
    logging.exception('Caught an error')

تحقق سريع

مراجعة

تابع التقدم