使用find查找比赛的获胜者

Question

我对熊猫中最大的熊猫有问题。我似乎弄不明白为什么每个名称的列都不能正确排序。即使第二列或第三列的分数较高，only似乎只在第一列起作用。我试着根据谁有最高的两个分数来找出获胜者。在下面的例子中，Jeff应该是赢家，但wins只适用于第一列，所以dan总是赢的。任何帮助都将不胜感激。

示例代码：

import pandas as pd

names = []
con = int(input("Number of Contestants: "))
maxSurfers = con #number of surfers
while len(names) < maxSurfers:
        name = input(" Enter your Name: ")
        names.append(name)
        print("Contestants")
        print(names)
else:
       print("Thank You for Participating!\n")
       print("Sign up is now closed\n")

score = {}
for name in names:
    numWaves = int(input("Number of Waves for "+name+": "))
    newScores = []
    for i in range(numWaves):
        newScores.append(float(input("Enter score wave: ")))
    score[name] = newScores
#newScores - most recent entry committed to score directory

df = pd.DataFrame(score)
for (columnName, columnData) in df.iteritems():
    winner = df.nlargest(2, names)
print(winner)

输出：

Number of Contestants: 3
 Enter your Name: dan
Contestants
['dan']
 Enter your Name: jeff
Contestants
['dan', 'jeff']
 Enter your Name: eric
Contestants
['dan', 'jeff', 'eric']
Thank You for Participating!

Sign up is now closed

Number of Waves for dan: 5
Enter score wave: 3.0
Enter score wave: 10.0
Enter score wave: 5.6
Enter score wave: 9.5
Enter score wave: 3.0
Number of Waves for jeff: 5
Enter score wave: 10.0
Enter score wave: 3.0
Enter score wave: 3.0
Enter score wave: 9.9
Enter score wave: 3.0
Number of Waves for eric: 5
Enter score wave: 3.0
Enter score wave: 1.0
Enter score wave: 5.6
Enter score wave: 9.5
Enter score wave: 6.3
    dan  jeff  eric
1  10.0   3.0   1.0
3   9.5   9.9   9.5

所需输出：

Number of Contestants: 3
 Enter your Name: dan
Contestants
['dan']
 Enter your Name: jeff
Contestants
['dan', 'jeff']
 Enter your Name: eric
Contestants
['dan', 'jeff', 'eric']
Thank You for Participating!

Sign up is now closed

Number of Waves for dan: 5
Enter score wave: 3.0
Enter score wave: 10.0
Enter score wave: 5.6
Enter score wave: 9.5
Enter score wave: 3.0
Number of Waves for jeff: 5
Enter score wave: 10.0
Enter score wave: 3.0
Enter score wave: 3.0
Enter score wave: 9.9
Enter score wave: 3.0
Number of Waves for eric: 5
Enter score wave: 3.0
Enter score wave: 1.0
Enter score wave: 5.6
Enter score wave: 9.5
Enter score wave: 6.3
    dan  jeff  eric
0   3.0  10.0   3.0
3   9.5   9.9   9.5

Answer 1

问题是，具有列列表(对于参数columns)的df.nlargest将首先根据列表中的第一个值(dan)进行排序，然后按第二个值(jeff)排序，最后是eric。

在nlargest文档页面的末尾对此进行了说明

pandas.DataFrame.nlargest

要获得每列的最高两个值，请尝试使用以下方法：

df = pd.DataFrame(score)

winner_df = pd.DataFrame()
for (columnName, columnData) in df.iteritems():
    winner = df.nlargest(2, columnName)[columnName].reset_index(drop= True)
    winner_df[columnName] = winner

print(winner_df)

输出：

    dan     jeff    eric
0   10.0    10.0    9.5
1   9.5     9.9     6.3

Answer 2

下面是我是如何修改代码的。

更改为：

df = pd.DataFrame(score)
winner_df = pd.DataFrame()
for (columnName, columnData) in df.iteritems():
    winner = df.nlargest(2, columnName)[columnName].reset_index(drop= True)
    winner_df[columnName] = winner
print(winner)

以下哪项输出：

Number of Waves for dan: 3
Enter score wave: 3.0
Enter score wave: 3.0
Enter score wave: 3.0
Number of Waves for jake: 3
Enter score wave: 10.0
Enter score wave: 9.9
Enter score wave: 3.0
Number of Waves for jeff: 3
Enter score wave: 4.0
Enter score wave: 3.0
Enter score wave: 5.0
0    5.0
1    4.0
Name: jeff, dtype: float64

注意到底哪里出了问题。