Question

words = {'apple', 'plum', 'pear', 'peach', 'orange', 'cherry', 'quince'}

d = {}  

for x in sorted(words):  
    if x not in d:  
        d[len(x)]=x  
d[len(x)].append(x)  

print(d)  
AttributeError: 'str' object has no attribute 'append'

The goal of the program is to have a multiple keys, distinguished by word length (i.e., 4, 5, or 6 letters), that store alphabetized values:

{4: 'pear', 'plum' 5: 'apple', 'peach' 6: 'cherry', 'orange', 'quince'}

I am having issues adding items to a key. What I am currently getting as my output is (without the append line):

{4: 'plum', 5: 'peach', 6: 'quince'}

so it seems to be erasing the previous loops entry. The update and append commands are coming back with errors.

Answer 1

您可以使用collections.defaultdict创建一个字典，根据字符长度存储每个项目：

from collections import defaultdict
d = defaultdict(list)
words = {'apple', 'plum', 'pear', 'peach', 'orange', 'cherry', 'quince'} 
for word in words:
   d[len(word)].append(word)

final_data = {a:sorted(b) for a, b in d.items()}

输出：

{4: ['pear', 'plum'], 5: ['apple', 'peach'], 6: ['cherry', 'orange', 'quince']}

此外，itertools.groupby可用于更短的解决方案：

import itertools
words = {'apple', 'plum', 'pear', 'peach', 'orange', 'cherry', 'quince'} 
new_words = {a:sorted(list(b)) for a, b in itertools.groupby(sorted(words, key=len), key=len)}

输出：

{4: ['pear', 'plum'], 5: ['apple', 'peach'], 6: ['cherry', 'orange', 'quince']}

Answer 2

你不能append到一个字符串;你必须从头开始制作你的字典值list。您还有两个检查，而不是一个：

dict是否有当前长度的单词？
列表中是否已有给定的单词？

试试这个：

size = len(x)
if size not in d:  
    d[size] = [x]
else:
    d[size].append(x)

Append items to existing/created keys in a dictionary

2 个答案: