将排名排序列添加到 Pandas Dataframe

Question

我知道这个问题可能看起来微不足道，但我在任何地方都找不到解决方案。我有一个非常大的 pandas 数据框df，看起来像这样：

                                            conference     IF2013  AR2013
0                                            HOTMOBILE  16.333333   31.50
1                                                 FOGA  13.772727   60.00
2                                              IEA/AIE  10.433735   28.20
3    IEEE Real-Time and Embedded Technology and App...  10.250000   29.00
4                  Symposium on Computational Geometry   9.880342   35.00
5                                                 WISA   9.693878   43.60
6                                                 ICMT   8.750000   22.00
7                                              Haskell   8.703704   39.00

我想在末尾添加一个额外的列，将其排序为 1,2,3,4 等。所以它看起来像这样：

                                               conference     IF2013    AR2013  Ranking 
    0                                            HOTMOBILE  16.333333   31.50   1  
    1                                                 FOGA  13.772727   60.00   2
    2                                              IEA/AIE  10.433735   28.20   3
    3    IEEE Real-Time and Embedded Technology and App...  10.250000   29.00   4  

我似乎不知道如何添加一个填充的额外列，该列只放置一系列连续的数字。

Answer 1

你可以试试：

df['rank'] = df.index + 1

print df
#                                          conference     IF2013  AR2013  rank
#0                                          HOTMOBILE  16.333333    31.5     1
#1                                               FOGA  13.772727    60.0     2
#2                                            IEA/AIE  10.433735    28.2     3
#3  IEEE Real-Time and Embedded Technology and App...  10.250000    29.0     4
#4                Symposium on Computational Geometry   9.880342    35.0     5
#5                                               WISA   9.693878    43.6     6
#6                                               ICMT   8.750000    22.0     7
#7                                            Haskell   8.703704    39.0     8

rank或者与参数一起使用ascending=False：

df['rank'] = df['conference'].rank(ascending=False)
print df
#                                          conference     IF2013  AR2013  rank
#0                                          HOTMOBILE  16.333333    31.5     1
#1                                               FOGA  13.772727    60.0     2
#2                                            IEA/AIE  10.433735    28.2     3
#3  IEEE Real-Time and Embedded Technology and App...  10.250000    29.0     4
#4                Symposium on Computational Geometry   9.880342    35.0     5
#5                                               WISA   9.693878    43.6     6
#6                                               ICMT   8.750000    22.0     7
#7                                            Haskell   8.703704    39.0     8