Python相当于golang的defer语句

要模拟defer fmt.Println(*a, i)示例,您可以使用contextlib.ExitStack:

#!/usr/bin/env python3
from contextlib import ExitStack
from functools import partial

print("counting")
with ExitStack() as stack:
    for i in range(10):
        a = i
        stack.callback(partial(print, a, i))

    x = 42
    a = x
    print("done")

产量

counting
done
9 9
8 8
7 7
6 6
5 5
4 4
3 3
2 2
1 1
0 0

可以轻松模拟互斥锁的情况:

def some_function(lock=Lock()):
    with lock:
        # whatever

Python的with语句与Go的延迟具有相似的目的.

Python中类似的代码是:

mutex = Lock()

def someFunction():
    with mutex:
        # Whatever you want, with as many return statements
        # as you want, wherever. Simply forget that you ever
        # locked a mutex, or that you have to remember to 
        # release it again.

我在那里做了一个(与2.x兼容):

@defers_collector
def func():
    f = open('file.txt', 'w')
    defer(lambda: f.close())

    defer(lambda : print("Defer called!"))

    def my_defer():
    recover()

    defer(lambda: my_defer())

    print("Ok )")
    panic("WTF?")

    print("Never printed (((")


func()
print("Recovered!")

来源defers_collector是:

# Go-style error handling

import inspect
import sys

def panic(x):
    raise Exception(x)

def defer(x):
    for f in inspect.stack():
    if '__defers__' in f[0].f_locals:
        f[0].f_locals['__defers__'].append(x)
        break

def recover():
    val = None
    for f in inspect.stack():
    loc = f[0].f_locals
    if f[3] == '__exit__' and '__suppress__' in loc:
        val = loc['exc_value']
        loc['__suppress__'].append(True)
        break
    return val

class DefersContainer(object):
    def __init__(self):
    # List for sustain refer in shallow clone
    self.defers = []

    def append(self, defer):
    self.defers.append(defer)

    def __enter__(self):
    pass

    def __exit__(self, exc_type, exc_value, traceback):
    __suppress__ = []
    for d in reversed(self.defers):
        try:
            d()
        except:
            __suppress__ = []
            exc_type, exc_value, traceback = sys.exc_info()
    return __suppress__


def defers_collector(func):
    def __wrap__(*args, **kwargs):
    __defers__ = DefersContainer()
    with __defers__:
        func(*args, **kwargs)
    return __wrap__

一个延迟部分的灵感来自于实施@DenisKolodin 答案是可以作为的一部分pygolang，2：

   wc = wcfs.join(zurl)    ?     wc = wcfs.join(zurl)
   defer(wc.close)         ?     try:
                           ?        ...
   ...                     ?        ...
   ...                     ?        ...
   ...                     ?     finally:
                           ?        wc.close()