import pandas as pd

# Create a DataFrame
df = pd.DataFrame({'A': [1, 2, 3, 4]})

# Add a new column by using a list of values
df['B'] = [20, 30, 40, 50]

# Print data frame
print(df)

>>>

   A   B
0  1  20
1  2  30
2  3  40
3  4  50