Question

我需要在python中写一个文件列表。我知道列表应该使用join方法转换为字符串，但由于我有一个元组，我感到困惑。我尝试了很多将变量更改为字符串等，这是我的第一次尝试：

def perform(text):
    repository = [("","")]
    fdist = nltk.FreqDist(some_variable)
    for c in some_variable:
        repository.append((c, fdist[c]))
    return ' '.join(repository)

但是它给了我以下错误：

Traceback (most recent call last):
  File "<pyshell#120>", line 1, in <module>
    qe = perform(entfile2)
  File "<pyshell#119>", line 14, in perform
    return ' '.join(repository)
TypeError: sequence item 0: expected string, tuple found

如何将列表'存储库'写入文件的任何想法？谢谢！

Answer 1

在将元组传递给join（）

之前将其转换为字符串

我已经相当彻底地重新安排了这个，这样：

您的功能现在是一个发电机（内存要求较低）
传入所需的格式 - 它返回您要求返回的格式
我猜some_variable是一个可报告的文本子集？

def perform(seq, tell=None, fmt=tuple):
    """
    @param seq:  sequence, items to be counted (string counts as sequence of char)
    @param tell: sequence, items to report on
    @param fmt:  function(item,count) formats output
    """
    # count unique items
    fdist = nltk.FreqDist(seq)

    if tell is None:
        # report on all seen items
        for item,num in fdist.iteritems():
            yield fmt(item,num)
    else:
        # report on asked-for items
        for item in tell:
            try:
                yield fmt(item,fdist[item])
            except KeyError:
                # tell contained an item not in seq!
                yield fmt(item,0)

# write to output file
fname = 'c:/mydir/results.txt'
with open(fname, 'w') as outf:
    outf.write(' '.join(perform(text, some_variable, ','.join)))

Answer 2

如果您想在磁盘上存储字典，请使用shelve：

import shelve

def get_repository(filename='repository'):
    # stores it's content on the disk
    store = shelve.DbfilenameShelf(filename)

    if not store: 
        # if it's empty fill it
        print 'creating fdist'
        # fdist = nltk.FreqDist(some_variable)
        fdist = dict(hello='There')
        store.update(fdist)
    return store

print get_repository()
# creating fdist
# {'hello': 'There'}
print get_repository()
# {'hello': 'There'}

Answer 3

首先应使用列表推导将元组列表转换为字符串列表，然后使用连接：

list_of_strings = ["(%s,%s)" % c for c in repository]
' '.join(list_of_strings)

python将列表写入文件

3 个答案: