1

I want to add a column to a data frame, and also set a list to each element of it, after the execution of below code, nothing changed,

df = pd.DataFrame({'A':[1,2,3],'B':[4,5,6]})  
df['C'] = 0 
for i in range(len(df)):
    lst = [6,7,8]
    data.iloc[i]['C'] = []
    data.iloc[i]['C'] = lst

Also, based on Assigning a list value to pandas dataframe, I tried df.at[i,'C'] on the above code, and the following error appeared: 'setting an array element with a sequence.'

Ch3steR
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Hossein Yousefi
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2 Answers2

3

You can use np.tile with np.ndarray.tolist

l = len(df)
df['C'] = np.tile([6,7,8],(l,1)).tolist()
df
   A  B          C
0  1  4  [6, 7, 8]
1  2  5  [6, 7, 8]
2  3  6  [6, 7, 8]
Ch3steR
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2

One idea is use list comprehension:

lst = [6,7,8]

df['C'] = [lst for _ in df.index]

print (df)
   A  B          C
0  1  4  [6, 7, 8]
1  2  5  [6, 7, 8]
2  3  6  [6, 7, 8]

In your solution for me working:

df['C'] = ''
for i in range(len(df)):
    lst = [6,7,8]
    df.iloc[i, df.columns.get_loc('C')] = lst
jezrael
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