python - 根据第二个列表中的位数对列表项进行分组

Question

目标是创建一个堆叠条形图，显示总共 360 秒(按秒)内推文(我从 tweepy 获得)的情绪。我有两个 list 。第一个按时间顺序对推文进行情感分析，第二个按时间顺序显示每秒的推文数量。

list1 = ("neg", "pos", "pos", "neu", "neg", "pos", "neu", "neu",...)
list2 = (2, 1, 3, 2,...)

现在我想创建某种嵌套循环并使用 list2 来计算列表 1 中的项目。然后我将拥有 3 个列表，其中每个情绪有 360 个值，我可以将其用于图表。它应该给我类似这样的输出:

lis_negative = (1, 0, 1, 0, ...)
lis_positive = (1, 1, 1, 0, ...)
lis_neutral = (0, 0, 1, 2, ...)

如何创建这个循环？是否有更简单的方法？除了 matplotlib 之外，我不想使用任何库。

Answer 1

代码:

from itertools import islice
from collections import Counter

def categorize(clas, amounts):
    cats = {'neg': [], 'pos': [], 'neu': []}
    clas = iter(clas)

    for a in amounts:
        cs = Counter(islice(clas, a)) # take a items
        for cat in cats:
            cats[cat].append(cs[cat])
    return cats

演示:

>>> t1 = ('neg', 'pos', 'pos', 'neu', 'neg', 'pos', 'neu', 'neu')
>>> t2 =  (2, 1, 3, 2)
>>> 
>>> categorize(t1, t2)
{'neg': [1, 0, 1, 0], 'neu': [0, 0, 1, 2], 'pos': [1, 1, 1, 0]}

根据要求，无需导入的解决方案:

def make_counter(iterable):
    c = {}
    for x in iterable:
        c[x] = c.get(x, 0) + 1
    return c

def categorize(clas, amounts):
    cats = {'neg': [], 'pos': [], 'neu': []}
    pos = 0

    for a in amounts:
        chunk = clas[pos:pos+a]
        pos += a
        cs = make_counter(chunk)
        for cat in cats:
            cats[cat].append(cs.get(cat, 0))
    return cats

编辑:更短的无导入解决方案:

def categorize(clas, amounts):
    cats = {k:[0]*len(amounts) for k in ('neg', 'pos', 'neu')}
    pos = 0

    for i, a in enumerate(amounts):
        chunk = clas[pos:pos+a]
        pos += a
        for c in chunk:
            cats[c][i] += 1

    return cats