用NaN值迭代連接熊貓中的列

Question

我有一個pandas.DataFrame數據框：

import pandas as pd

df = pd.DataFrame({"x": ["hello there you can go home now", "why should she care", "please sort me appropriately"], 
    "y": [np.nan, "finally we were able to go home", "but what about meeeeeeeeeee"],
    "z": ["", "alright we are going home now", "ok fine shut up already"]})

cols = ["x", "y", "z"]

我想迭代地連接這些列，而不是像這樣寫：

df["concat"] = df["x"].str.cat(df["y"], sep = " ").str.cat(df["z"], sep = " ")

我知道將三列匯總起來似乎很瑣碎，但實際上我有30列。因此，我想做些類似的事情：

df["concat"] = df[cols[0]]
for i in range(1, len(cols)):
    df["concat"] = df["concat"].str.cat(df[cols[i]], sep = " ")

現在，初始df["concat"] = df[cols[0]]行可以正常工作，但是位置df.loc[1, "y"]的NaN值使連接混亂。 最終，由於這一空值，整個1行在df["concat"]以NaN結尾。 我該如何解決？ 我需要指定pd.Series.str.cat有某些選項嗎？

Answer 1

選項1

pd.Series(df.fillna('').values.tolist()).str.join(' ')

0                    hello there you can go home now  
1    why should she care finally we were able to go...
2    please sort me appropriately but what about me...
dtype: object

選項2

df.fillna('').add(' ').sum(1).str.strip()

0                      hello there you can go home now
1    why should she care finally we were able to go...
2    please sort me appropriately but what about me...
dtype: object

Answer 2

選項3

In [3061]: df.apply(lambda x: x.str.cat(sep=''), axis=1)
Out[3061]:
0                      hello there you can go home now
1    why should she carefinally we were able to go ...
2    please sort me appropriatelybut what about mee...
dtype: object