我有兩個數據集。我想使用索引進行合并。第一個數據集：index A B C01/01/2010 15 20 3015/01/2010 12 15 2517/02/2010 14 13 3519/02/2010 11 10 222nt 數據集：index year month price0 2010 january 701 2010 february 80我希望他們像這樣加入：index A B C price01/01/2010 15 20 30 7015/01/2010 12 15 25 7017/02/2010 14 13 35 8019/02/2010 11 10 22 80問題是如何使用兩列（year以及month第二個數據集）來創建臨時 datetime index。
2 回答
阿晨1998
TA貢獻2037條經驗 獲得超6個贊
試試這個，通過從中提取.month_name()和 year( .dt.year)df1并將其與df2
>>> df1
index A B C
0 01/01/2010 15 20 30
1 15/01/2010 12 15 25
2 17/02/2010 14 13 35
3 19/02/2010 11 10 22
>>> df2
index year month price
0 0 2010 january 70
1 1 2010 february 80
# merging df1 and df2 by month and year.
>>> df1.merge(df2,
left_on = [pd.to_datetime(df1['index']).dt.year,
pd.to_datetime(df1['index']).dt.month_name().str.lower()],
right_on = ['year', 'month'])
輸出：
index_x A B C index_y year month price
0 01/01/2010 15 20 30 0 2010 january 70
1 15/01/2010 12 15 25 0 2010 january 70
2 17/02/2010 14 13 35 1 2010 february 80
3 19/02/2010 11 10 22 1 2010 february 80
九州編程
TA貢獻1785條經驗 獲得超4個贊
這是愚蠢的答案！我相信你可以做得比這更聰明:) 但考慮到你的表是一個字典列表（你可以輕松地將你的 SQL 表轉換為這種格式），這很有效。我知道這不是一個干凈的解決方案，但是您要求一個簡單的解決方案，這可能是最容易理解的:)
months = {'january': "01",
'february': "02",
'march': "03",
'april':"04",
'may': "05",
'june': "06",
'july': "07",
'august': "08",
'september': "09",
'october': "10",
'november': "11",
'december': "12"}
table1 = [{'index': '01/01/2010', 'A': 15, 'B': 20, 'C': 30},
{'index': '15/01/2010', 'A': 12, 'B': 15, 'C': 25},
{'index': '17/02/2010', 'A': 14, 'B': 13, 'C': 35},
{'index': '19/02/2010', 'A': 11, 'B': 10, 'C': 22}]
table2 = [{'index': 0, 'year': 2010, 'month': 'january', 'price':70},
{'index': 1, 'year': 2010, 'month': 'february', 'price':80}]
def joiner(table1, table2):
for row in table2:
row['tempDate'] = "{0}/{1}".format(months[row['month']], str(row['year']))
for row in table1:
row['tempDate'] = row['index'][3:]
table3 = []
for row1 in table1:
row3 = row1.copy()
for row2 in table2:
if row2['tempDate'] == row1['tempDate']:
row3['price'] = row2['price']
break
table3.append(row3)
return(table3)
table3 = joiner(table1, table2)
print(table3)
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