python - Pickle - 如果存在则加载变量或创建并保存它

Question

如果变量已经存在，是否有更好的方法使用 pickle 加载变量，或者如果不存在则创建并转储它？

if os.path.isfile("var.pickle"):
    foo = pickle.load( open( "var.pickle", "rb" ) )
else:
    foo = 3
    pickle.dump( foo, open( "var.pickle", "wb" ) )

Answer 1

您可以关注EAFP principle和 ask for forgiveness :

import pickle

try:
    foo = pickle.load(open("var.pickle", "rb"))
except (OSError, IOError) as e:
    foo = 3
    pickle.dump(foo, open("var.pickle", "wb"))