Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
660 views
in Technique[技术] by (71.8m points)

sorting - How to sort dictionaries by keys in Python

Can anyone tell me how I can sort this:

{'a': [1, 2, 3], 'c': ['one', 'two'], 'b': ['blah', 'bhasdf', 'asdf'], 'd': ['asdf', 'wer', 'asdf', 'zxcv']}

into

{'a': [1, 2, 3], 'b': ['blah', 'bhasdf', 'asdf'], 'c': ['one', 'two'],'d': ['asdf', 'wer', 'asdf', 'zxcv']}

? Thanks!

UPDATE 1, code sample:

So I am doing linguistics. One article is broken down to words that are stored in a database and have all kinds of properties including para ID and sentence ID. The task: trying to rebuild the original text.

Get 500 consecutive words from DB

words = Words.objects.all()[wordId:wordId+500]
# I first create paragraphs, through which I can loop later in my django template,
# and in each para will be a list of words (also dictionaries). 
# So i am trying to get a dictionary with values that are lists of dictionaries. 
# 'pp' i make just for shorthanding a long-named variable.
paras={}
para_high = para_low =  words[0].belongs_to_paragraph
for w in words:
    last_word = w
    pp = w.belongs_to_paragraph
    if pp >para_high:
        para_high = pp
    if pp < para_low:
        para_low = pp
    if pp in paras:
        paras[pp].append(w)
    else:
        list = [w]
        paras[pp] = list
# Since there are blank lines between paragraphs, in rebuilding the text as it 
    #  looked originally, I need to insert blank lines. 
    # Since i have the ID's of the paragraphs and they go somewhat like that: 1,3,4,8,9 
    #(the gaps between 1 & 3 and 4 & 8 i have to fill in with something else, 
    # which is why i had para_low and para_high to loop the range. 
isbr = True
for i in range(para_low, para_high+1):
    if i in paras:
        isbr = True
    else:
        if isbr:
            paras[i]=['break']
            isbr = False
        else:
            paras[i]=[]

At this point, however, if I try to loop the dict and rebuild the text, some later id'd paragraphs come before previous ones, and that just doesn't do it.

UPDATE 2, loop code:

        {% for k,v in wording.iteritems()  %}
        {% if v[0] == 'break' %}
        <br/>
        {% else %}
        </div><div class="p">{% for word in v %}{% if word.special==0%} {% endif %}<span class="word {% if word.special == 0%}clickable{% endif%}" wid="{{word.id}}" special="{{word.special}}" somethingElse={{word.somethingElse}}>{{ word.word }}</span>{% endfor %}
        {% endif %}
    {% endfor %}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Dicts don't have an order.

You can call sorted but this just gives you a sorted list of the keys:

>>> sorted(d)
['a', 'b', 'c', 'd']

You can treat it as an iterable and sort the key-value tuples, but then you've just got a list of tuples. That's not the same as a dict.

>>> sorted(d.items())
[
 ('a', [1, 2, 3]),
 ('b', ['blah', 'bhasdf', 'asdf']),
 ('c', ['one', 'two']),
 ('d', ['asdf', 'wer', 'asdf', 'zxcv'])
]

If you are using Python 2.7 or newer you could also consider using an OrderedDict.

dict subclass that remembers the order entries were added

For example:

>>> d = collections.OrderedDict(sorted(d.items()))
>>> for k, v in d.items():
>>>     print k, v
a [1, 2, 3]
b ['blah', 'bhasdf', 'asdf']
c ['one', 'two']
d ['asdf', 'wer', 'asdf', 'zxcv']

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...