Python contextlib.ExitStack.pop_all用法及代碼示例

用法: pop_all()

將回調堆棧轉移到新的 ExitStack 實例並返回它。此操作不會調用回調 - 相反，現在將在新堆棧關閉時調用它們(在 with 語句的末尾顯式或隱式地)。

例如，一組文件可以作為 “all or nothing” 操作打開，如下所示：

with ExitStack() as stack:
    files = [stack.enter_context(open(fname)) for fname in filenames]
    # Hold onto the close method, but don't call it yet.
    close_files = stack.pop_all().close
    # If opening any file fails, all previously opened files will be
    # closed automatically. If all files are opened successfully,
    # they will remain open even after the with statement ends.
    # close_files() can then be invoked explicitly to close them all.

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