我到处搜寻,但找不到任何相关内容…
我正在寻找一种方法来将字典保存到文件中,然后在以后通过读取文件将其加载回变量中。
文件的内容不必是“人类可读的”,它可以随心所欲地混乱。
谢谢-Hyflex
import cPickle as pickle BDICT = {} ## Automatically generated START name = "BOB" name_title = name.title() count = 5 BDICT[name_title] = count name = "TOM" name_title = name.title() count = 5 BDICT[name_title] = count name = "TIMMY JOE" name_title = name.title() count = 5 BDICT[name_title] = count ## Automatically generated END if BDICT: with open('DICT_ITEMS.txt', 'wb') as dict_items_save: pickle.dump(BDICT, dict_items_save) BDICT = {} ## Wiping the dictionary ## Usually in a loop firstrunDICT = True if firstrunDICT: with open('DICT_ITEMS.txt', 'rb') as dict_items_open: dict_items_read = dict_items_open.read() if dict_items_read: BDICT = pickle.load(dict_items_open) firstrunDICT = False print BDICT
错误:
Traceback (most recent call last): File "C:\test3.py", line 35, in <module> BDICT = pickle.load(dict_items_open) EOFError
一些人推荐shelve-我没有使用过它,我也不会敲它。我使用了pickle / cPickle,将提供以下方法:
shelve
有 许多 原因使您选择使用Pickle(或其显着的更快的变体cPickle)。简而言之, Pickle 是一种在过程之外存储对象的方法。
Pickle不仅为您提供了在python进程之外存储对象的选项,而且还以序列化的方式进行存储。含义, 先进先出 行为(FIFO)。
import pickle ## I am making up a dictionary here to show you how this works... ## Because I want to store this outside of this single run, it could be that this ## dictionary is dynamic and user based - so persistance beyond this run has ## meaning for me. myMadeUpDictionary = {"one": "banana", "two": "banana", "three": "banana", "four": "no-more"} with open("mySavedDict.txt", "wb") as myFile: pickle.dump(myMadeUpDictionary, myFile)
如果然后进入刚刚创建的文件(现在位于文件系统上),则可以看到其内容。这很乱-丑陋-而且不是很有见地。
nammer@crunchyQA:~/workspace/SandBox/POSTS/Pickle & cPickle$ cat mySavedDict.txt (dp0 S'four' p1 S'no-more' p2 sS'three' p3 S'banana' p4 sS'two' p5 g4 sS'one' p6 g4 s.
要将其返回到我们的程序中,我们只需执行以下操作:
import pickle with open("mySavedDict.txt", "rb") as myFile: myNewPulledInDictionary = pickle.load(myFile) print myNewPulledInDictionary
它提供以下返回:
{'four': 'no-more', 'one': 'banana', 'three': 'banana', 'two': 'banana'}
这些天您不会看到很多人使用泡菜-我想不出为什么您会想使用泡菜的第一个实现,尤其是当cPickle所做的事情相同(或多或少)时但是快很多!
因此,您可以懒惰并这样做:
import cPickle as pickle
如果您已经构建了使用泡菜的东西,那就太好了…但是 我认为这是一个不好的建议,我完全希望被推荐甚至被指责! (您应该真正查看使用原始代码的旧实现,pickle并查看是否需要更改任何内容以遵循cPickle模式;如果您使用的是旧版代码或生产代码,则可以节省重构时间(查找/替换所有实例)用cPickle腌制)。
pickle
cPickle
否则,只需:
import cPickle
在您看到对pickle库的引用的任何地方,只需进行相应的替换即可。它们具有相同的load()和dump()方法。
警告警告 我不想再写这篇文章了,但是我似乎有这样的痛苦记忆,那就是不区分load()和loads(),和dump()和dumps()。该死的…那真是我的愚蠢!简短的答案是load()/ dump()会对类似文件的对象执行此操作,而load()/ dumps()将对类似字符串的对象执行类似的行为(有关更多信息,请参见API,此处)。
load()
loads()
dump()
dumps()
同样,我还没有使用过shelve,但是,如果它对您(或其他人)有用,那么可以!
最后,您需要dict_items_read = dict_items_open.read()从上下文管理器中删除。该文件已经打开并可以读入。您不会像读取文本文件那样将其读入字符串中…它存储的是腌制的python对象。这不是为了眼睛!它用于load()。
dict_items_read = dict_items_open.read()
您修改的代码…对我来说很好用(复制/粘贴并运行下面的代码,看它是否有效)。请注意,在底部附近,我已删除read()了文件对象。
read()
import cPickle as pickle BDICT = {} ## Automatically generated START name = "BOB" name_title = name.title() count = 5 BDICT[name_title] = count name = "TOM" name_title = name.title() count = 5 BDICT[name_title] = count name = "TIMMY JOE" name_title = name.title() count = 5 BDICT[name_title] = count ## Automatically generated END if BDICT: with open('DICT_ITEMS.txt', 'wb') as dict_items_save: pickle.dump(BDICT, dict_items_save) BDICT = {} ## Wiping the dictionary ## Usually in a loop firstrunDICT = True if firstrunDICT: with open('DICT_ITEMS.txt', 'rb') as dict_items_open: BDICT = pickle.load(dict_items_open) firstrunDICT = False print BDICT