python pandas 右填充值

Question

我正在尝试复制一个类似“正确填充”的 excel 函数，该函数会正确填充值，直到下一个值不为 null/nan/empty。仅当紧接的下一行中的值不为空或不为“nan”时，才执行此“右填充”练习。 我有以下 Pandas 数据框数据集。我当前的输入表是“有”。我的输出表是“想要的”。

import pandas as pd
have = pd.DataFrame({ \
"0": pd.Series(["abc","1","something here"]) \
,"1": pd.Series(["","2","something here"]) \
,"2": pd.Series(["","3","something here"]) \
,"3": pd.Series(["something","1","something here"]) \
,"4": pd.Series(["","2","something here"]) \
,"5": pd.Series(["","","something here"]) \
,"6": pd.Series(["","","something here"]) \
,"7": pd.Series(["cdf","5","something here"]) \
,"8": pd.Series(["","6","something here"]) \
,"9": pd.Series(["xyz","1","something here"]) \
})

want = pd.DataFrame({ \
"0": pd.Series(["abc","1","something here"]) \
,"1": pd.Series(["abc","2","something here"]) \
,"2": pd.Series(["abc","3","something here"]) \
,"3": pd.Series(["something","1","something here"]) \
,"4": pd.Series(["something","2","something here"]) \
,"5": pd.Series(["","","something here"]) \
,"6": pd.Series(["","","something here"]) \
,"7": pd.Series(["cdf","5","something here"]) \
,"8": pd.Series(["cdf","6","something here"]) \
,"9": pd.Series(["xyz","1","something here"]) \
})

Answer 1

在第 2 行创建一个 bool 掩码。

• 测试它是否为空(None 或 np.nan)
• 测试它是否等于一个空字符串''

作业

• 使用loc赋值
• replace 默认情况下向前填充空值。

---

cond = have.loc[1].isnull() | have.loc[1].ne('')
have.loc[0, cond] = have.loc[0, cond].replace('', None)
have

---

如果空格 '' 是空格 ' ' 我们可以使用 strip

cond = have.loc[1].isnull() | have.loc[1].ne('')
have.loc[0, cond] = have.loc[0, cond].str.strip().replace('', None)
have