python - 将两列 Pandas 数据框合并为一个字符串

Question

我有以下数据框

import pandas as pd
import numpy as np

df = pd.DataFrame(data=[['yes',8],['yes',7],['no',np.nan],['yes',7],['no',np.nan]],columns=['passed','score'])

Out[8]: 
  passed  score
0    yes    8.0
1    yes    7.0
2     no    NaN
3    yes    7.0
4     no    NaN

我想将通过的列和得分合并为如下的 1 列

Out[10]: 
  passed
0  yes_8
1  yes_7
2     no
3  yes_7
4     no

我的尝试是 df["passed"].map(str) + '_' + df["score"].map(str) 但它没有我想要的那么干净你能帮帮我吗？

Answer 1

将 df.apply 与 axis=1 一起使用

演示:

import pandas as pd
import numpy as np

df = pd.DataFrame(data=[['yes',8],['yes',7],['no',np.nan],['yes',7],['no',np.nan]],columns=['passed','score'])
df["New"] = df.apply(lambda x: "yes_{}".format(int(x["score"])) if x["passed"] == "yes" else "no", axis=1)
print(df)

输出:

  passed  score    New
0    yes    8.0  yes_8
1    yes    7.0  yes_7
2     no    NaN     no
3    yes    7.0  yes_7
4     no    NaN     no