Question

我有一个由excel float格式的日期组成的列表列表（自1996年7月5日起每分钟）和一个与每个日期相关的整数值，如下所示：header=FALSE。我需要创建一个由所有日期（没有小时或分钟）组成的新列表，以及该日期内所有日期时间的值的总和。换句话说，[[datetime,integer]...]和listolists[x][0] >= math.floor(listolists[x][0])时每个日期的值的总和是多少。感谢

Answer 1

由于您没有提供任何实际数据（只是您使用的数据结构，嵌套列表），我在下面创建了一些虚拟数据，以演示如何在Python中执行SUMIFS类型的问题

from datetime import datetime
import numpy as np
import pandas as pd

dates_list = []

# just take one month as an example of how to group by day
year = 2015
month = 12

# generate similar data to what you might have
for day in range(1, 32):
    for hour in range(1, 24):
        for minute in range(1, 60):
            dates_list.append([datetime(year, month, day, hour, minute), np.random.randint(20)])

# unpack these nested list pairs so we have all of the dates in 
# one list, and all of the values in the other
# this makes it easier for pandas later
dates, values = zip(*dates_list)

# to eventually group by day, we need to forget about all intra-day data, e.g.
# different hours and minutes. we only care about the data for a given day, 
# not the by-minute observations. So, let's set all of the intra-day values to
# some constant for easier rolling-up of these dates.
new_dates = []

for d in dates:
    new_d = d.replace(hour = 0, minute = 0)
    new_dates.append(new_d)

# throw the new dates and values into a pandas.DataFrame object
df = pd.DataFrame({'new_dates': new_dates, 'values': values})

# here's the SUMIFS function you're looking for
grouped = df.groupby('new_dates')['values'].sum()

让我们看看结果：

>>> print(grouped.head())
new_dates
2015-12-01    12762
2015-12-02    13292
2015-12-03    12857
2015-12-04    12762
2015-12-05    12561
Name: values, dtype: int64

编辑：如果您希望以嵌套列表格式返回这些新的分组数据，请执行以下操作：

new_list = [[date, value] for date, value in zip(grouped.index, grouped)]

Answer 2

谢谢大家。这是我能提出的最简单的代码，它不需要熊猫：

for row in listolist:
     for k in (0, 1):
         row[k] = math.floor(float(row[k]))
date = {}
for d,v in listolist:
    if d in date:
        date[math.floor(d)].append(v)
    else:
        date[math.floor(d)] = [v]
result = [(d,sum(v)) for d,v in date.items()]

Python SumIfs列表日期列表

2 个答案: