Question

有什么方法可以将矩阵返回向量吗？我不知道矩阵中元素的数量，所以说矩阵有n个元素。

下面是我要转换表格的示例。任何帮助，指导，建议，推荐将不胜感激。

原始data.csv：

,January,February,March,April,May,June,July,August,September,October,November,December
2019,1,2,3,4,5,6,7,8,9,10,11,12
2018,13,14,15,16,17,18,19,20,21,22,23,24
2017,25,26,27,28,29,30,31,32,33,34,35,36

the link for csv files

raw=pd.read_csv('raw data.csv')
raw.head()
    Unnamed: 0  January February    March   April   May June    July    August  September   October November    December
0   2019    1   2   3   4   5   6   7   8   9   10  11  12
1   2018    13  14  15  16  17  18  19  20  21  22  23  24
2   2017    25  26  27  28  29  30  31  32  33  34  35  36

final=pd.read_csv('Final.csv')
final.head(20)
    Year&Month  Value
0   2019 January    1
1   2019 February   2
2   2019 March  3
3   2019 April  4
4   2019 May    5
5   2019 June   6
6   2019 July   7
7   2019 August 8
8   2019 September  9
9   2019 October    10
10  2019 November   11
11  2019 December   12
12  2018 January    13
13  2018 February   14
14  2018 March  15
15  2018 April  16
16  2018 May    17
17  2018 June   18
18  2018 July   19
19  2018 August 20```

Answer 1

您可以使用pandas stack

df = pd.read_csv(r'raw data.csv')
df.set_index(df.columns[0]).stack().reset_index()

出局：

    Unnamed: 0  level_1 0
0   2019    January 1
1   2019    February    2
2   2019    March   3
3   2019    April   4
4   2019    May 5
5   2019    June    6
6   2019    July    7
7   2019    August  8
8   2019    September   9
9   2019    October 10
10  2019    November    11
11  2019    December    12
12  2018    January 13
13  2018    February    14

如何将矩阵返回向量

1 个答案: