Write a Pandas program to convert the first column of a DataFrame as a Series

import pandas as pd
d = {'col1': [1, 2, 3, 4, 7, 11], 'col2': [4, 5, 6, 9, 5, 0], 'col3': [7, 5, 8, 12, 1,11]}
df = pd.DataFrame(data=d)
print("Original DataFrame")
print(df)
s1 = df.ix[:,0]
print("\n1st column as a Series:")
print(s1)
print(type(s1))

Sample Output:

Original DataFrame
   col1  col2  col3
0     1     4     7
1     2     5     5
2     3     6     8
3     4     9    12
4     7     5     1
5    11     0    11

1st column as a Series:
0     1
1     2
2     3
3     4
4     7
5    11
Name: col1, dtype: int64
<class 'pandas.core.series.Series'>