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通过if-else语句创建列

dataframe python

spearrow · 技术社区 · 11 月前

我有一个4列的数据框。列为: 首页_团队等待_团队首页_团队_煤炭等待_团队_目标

我想用目标来创建一个赢家专栏。我写了下面的代码,但当我运行它时,我只得到获胜者栏中的主队。


A = ['A', '1', 'D', '2']
B = ['B', '2', 'E', '2']
C = ['C', '3', 'F', '2']

df = pd.DataFrame(np.array([A,B,C]), columns = ['Home_team', 'Home_team_goal', 'Away_team', 'Away_team_goal'])

df['Home_team_goal'] = pd.to_numeric(df['Home_team_goal'])
df['Away_team_goal'] = pd.to_numeric(df['Away_team_goal'])



df['Average'] = df['Home_team_goal'] - df['Away_team_goal']

df['Winner'] = ''

for i, e in enumerate(df['Average']):
    if e > 0:
        df['Winner'] = df['Home_team']
    elif e < 0:
        df['Winner'] = df['Away_team']
    else:
        df['Winner'] = 'Tie'

3 回复 | 直到 11 月前

user19077881 11 月前

这可以使用Numpy.select完成:

import numpy as np
cond1 = df['Home_team_goal'] > df['Away_team_goal']
cond2 = df['Home_team_goal'] < df['Away_team_goal']

df['Winner'] = np.select([cond1, cond2], ['Home_team', 'Away_team'], default = 'Tie')

Orhan Serçe 11 月前

这里有另一种方法:

def Winner(x):
if x > 0:
    return 1
elif x < 0:
    return 2
else:
    return 0

df['Winner'] = df['Average'].apply(Winner)

ticktalk 11 月前

另外(在这里键入太尴尬了,无法发表评论。。。。

df['Average'] = df['Home_team_goal'] - df['Away_team_goal']

将投掷 TypeError: unsupported operand type(s) for -: 'str' and 'str'

你需要将它们转换为整数

df['Home_team_goal'] = df['Home_team_goal'].astype(int)
df['Away_team_goal'] = df['Away_team_goal'].astype(int)

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