python with

三个代码等价。with还可以很好的处理上下文环境产生的异常。

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file = open("/tmp/foo.txt")
data = file.read()
file.close()
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file = open("/tmp/foo.txt")
try:
    data = file.read()
finally:
    file.close()
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with open("/tmp/foo.txt") as file:
    data = file.read()
原文地址:https://www.cnblogs.com/tina-ma/p/4077964.html