Question

我有一个字典，我必须根据值集中的单词替换所有键。所以我的字典是：

  { 23: {'score': -8.639, 'char': False, 'word': 'positive'} }
  { 56: {'score': -5.6, 'char': False, 'word': 'neutral'} }
  { 89: {'score': -8.9, 'char': False, 'word': 'positive'} }
  { 34: {'score': -2.3, 'char': Tru, 'word': 'negative'} }

如果词典的值部分，即关键词是肯定的，那么它应该用+1代替键23，对于中性，键56用0代替，对于负代表，键34用-1代替。输出结果如下：

  { +1: {'score': -8.639, 'char': False, 'word': 'positive'} }
  { 0: {'score': -5.6, 'char': False, 'word': 'neutral'} }
  { +1: {'score': -8.9, 'char': False, 'word': 'positive'} }
  { -1: {'score': -2.3, 'char': Tru, 'word': 'negative'} }

这是我的代码：

for n, line in enumerate(sys.stdin,1):
    d = ast.literal_eval(line)
    items = d.values()[0].items()
    if re.match("positive",d.get('sentimentoftweet')):
       n = str.replace(str(n),"+1")
    else:
       n = str.replace(str(n),"0")

它不能正常工作并给我这个错误：

Traceback (most recent call last):
File "./linear.py", line 33, in <module>
for thing in d:
File "./linear.py", line 22, in gen_with_appropriate_name
if re.match("positive",d.get('sentimentoftweet')):
File "/usr/lib/python2.7/re.py", line 137, in match
return _compile(pattern, flags).match(string)
TypeError: expected string or buffer

Answer 1

您将错误的密钥传递给re.match。如果缺少键dict.get，则返回None，请使用d.get('word')。

>>> import re
>>> re.match('foo', None)
Traceback (most recent call last):
  File "<ipython-input-43-c75223170494>", line 1, in <module>
    re.match('foo', None)
  File "/usr/lib/python3.3/re.py", line 156, in match
    return _compile(pattern, flags).match(string)
TypeError: expected string or buffer

您可以使用==匹配字符串或值：

if d.get('word') == 'positive':
   #do something
elif d.get('word') == 'negative'
   #do something else

<强>代码：

import sys, ast
for line in sys.stdin:
    d = ast.literal_eval(line)
    key = list(d)[0]            #dictionary with just one key.
    if d[key]['word'] == 'positive':
        print {'+1': d[key]}
    elif d[key]['word'] == 'negative':
        print {'-1': d[key]}
    elif d[key]['word'] == 'neutral':
        print {'0': d[key]}

<强>输出：

{'+1': {'char': False, 'score': -8.639, 'word': 'positive'}}
{'0': {'char': False, 'score': -5.6, 'word': 'neutral'}}
{'+1': {'char': False, 'score': -8.9, 'word': 'positive'}}
{'-1': {'char': True, 'score': -2.3, 'word': 'negative'}}

Answer 2

问题是d.get('word')没有查看嵌套字典。

Answer 3

也许是这样的：

#!/usr/local/cpython-3.3/bin/python

import pprint
import collections

dict_ = { 23: {'score': -8.639, 'char': False, 'word': 'positive'},
    56: {'score': -5.6, 'char': False, 'word': 'neutral'},
    89: {'score': -8.9, 'char': False, 'word': 'positive'},
    34: {'score': -2.3, 'char': True, 'word': 'negative'},
    }

new_dict = collections.defaultdict(list)
for key, value in dict_.items():
    if value['word'] == 'positive':
        key = '+1'
    elif value['word'] == 'neutral':
        key = '0'
    elif value['word'] == 'negative':
        key = '-1'
    else:
        raise ValueError('word not positive, neutral or negative')
    new_dict[key].append(value)

pprint.pprint(new_dict)

多行词典：根据值中的单词替换键

3 个答案: