How to add a list as a new column to an existing DataFrame in Python?

The simplest way to append a list as a new column to a Pandas DataFrame in Python is to use the syntaxe df[columnName]=list. Let's consider the following dataframe:

>>> import pandas as pd
>>> df = pd.DataFrame([[1, 2], [4, 5]], columns = ["col1", "col2"])
   col1  col2
0     1     2
1     4     5

The following command appends a list to the DataFrame as a new column named col3:

>>> df['col3'] = [3, 6]
   col1  col2  col3
0     1     2     3
1     4     5     6

>>> df['col3'] = [3, 4]
   col1  col2  col3
0     1     2     3
1     4     5     4

The simplest way to append a list as a column to a Pandas DataFrame in Python is to use the syntaxe df[columnName]=list. Let's consider the following dataframe:

>>> import pandas as pd
>>> df = pd.DataFrame([[1, 2], [4, 5]], columns = ["col1", "col2"])
   col1  col2
0     1     2
1     4     5

The following command appends a list to the DataFrame as a new column named col3:

>>> df['col3'] = [3, 4]
   col1  col2  col3
0     1     2     3
1     4     5     4