python - 如何在 Python 中遍历 defaultdict(list)？

Question

我如何在 Python 中遍历 defaultdict(list)？有没有更好的方法在 Python 中创建列表字典？我已经尝试了正常的 iter(dict) 但我遇到了错误:

>>> import para
>>> para.print_doc('./sentseg_en/essentials.txt')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "para.py", line 31, in print_doc
    for para in iter(doc):
TypeError: iteration over non-sequence

主类:

import para
para.print_doc('./foo/bar/para-lines.txt')

para.pyc:

# -*- coding: utf-8 -*-
## Modified paragraph into a defaultdict(list) structure
## Original code from http://code.activestate.com/recipes/66063/
from collections import defaultdict
class Paragraphs:
    import sys
    reload(sys)
    sys.setdefaultencoding('utf-8')
    # Separator here refers to the paragraph seperator,
    #  the default separator is '\n'.
    def __init__(self, filename, separator=None):
        # Set separator if passed into object's parameter,
        #  else set default separator as '\n'
        if separator is None:
            def separator(line): return line == '\n'
        elif not callable(separator):
            raise TypeError, "separator argument must be callable"
        self.separator = separator
        # Reading lines from files into a dictionary of lists
        self.doc = defaultdict(list)
        paraIndex = 0
        with open(filename) as readFile:
            for line in readFile:
                if line == separator:
                    paraIndex+=1
                else:
                    self.doc[paraIndex].append(line)

# Prints out populated doc from txtfile
def print_doc(filename):
    text = Paragraphs(filename)
    for para in iter(text.doc):
        for sent in text.doc[para]:
            print "Para#%d, Sent#%d: %s" % (
                para, text.doc[para].index(sent), sent)

例如./foo/bar/para-lines.txt 看起来像这样:

This is a start of a paragraph.
foo barr
bar foo
foo foo
This is the end.

This is the start of next para.
foo boo bar bar
this is the end.

主类的输出应该是这样的:

Para#1,Sent#1: This is a start of a paragraph.
Para#1,Sent#2: foo barr
Para#1,Sent#3: bar foo
Para#1,Sent#4: foo foo
Para#1,Sent#5: This is the end.

Para#2,Sent#1: This is the start of next para.
Para#2,Sent#2: foo boo bar bar
Para#2,Sent#3: this is the end.

Answer 1

线路问题

for para in iter(doc):

doc 是 Paragraph 的实例，而不是 defaultdict。您在 __init__ 方法中使用的默认字典超出范围并丢失。所以你需要做两件事:

1. 将__init__方法中创建的doc保存为实例变量(例如self.doc)。

2. 要么使 Paragraphs 本身可迭代(通过添加 __iter__ 方法)，要么允许它访问创建的 doc 对象。