如何将更长的列表附加到数据框

Question

I wanna append a longer list to dataframe .But get an error ValueError: Length of values (4) does not match length of index (3)

import pandas as pd

df = pd.DataFrame({'Data': ['1', '2', '3']})

df['Data2'] =['1', '2', '3', '4']

print(df)

How can I fix it .

Answer 1

Use DataFrame.reindex for add new rows by maximal length by new list or original DataFrame, if length of list should be changed, sometimes same length or sometimes length is shorter:

df = pd.DataFrame({'Data': ['1', '2', '3']})

L = ['1', '2', '3', '4']

df = df.reindex(range(max(len(df), len(L))))
df['Data2'] = L
print (df)
  Data Data2
0    1     1
1    2     2
2    3     3
3  NaN     4

If always is length of list longer:

df = df.reindex(range(len(L)))
df['Data2'] = L

Answer 2

You can try using pd.concat here but convert your list to a Series then use pd.concat

l = ['1', '2', '3', '4']
pd.concat([df, pd.Series(l, name='Data2')], axis=1)

  Data Data2
0    1     1
1    2     2
2    3     3
3  NaN     4