Pandas Data Series: Convert the first column of a DataFrame as a Series

Last update on May 01 2025 12:54:12 (UTC/GMT +8 hours)

8. DF Column to Series

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

Sample Solution :

Python Code :

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)

# Using iloc
s1 = df.iloc[:, 0]

# Alternatively, you can directly reference the column by name
#s1 = df['col1']

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'>

Explanation:

Here is the breakdown of the above exercise:

Import Pandas Library:
```
import pandas as pd
```
This line imports the Pandas library and assigns it the alias "pd" for easier reference.
Create a DataFrame:
```
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)
```
This code creates a DataFrame (df) using a dictionary (d). Each key-value pair in the dictionary represents a column in the DataFrame.
Print Original DataFrame:
```
print("Original DataFrame") print(df)
```
This prints the original DataFrame (df) to the console.
Extract the First Column as a Series:
```
s1 = df.iloc[:, 0]
or alternatively:
# s1 = df['col1']
```
This line extracts the first column from the DataFrame as a Series (s1). The iloc[:, 0] indexer is used to select all rows (:) from the first column (0). Alternatively, you can directly reference the column by name (df['col1']).
Print the Result:
```
print("\n1st column as a Series:") print(s1)
```
This prints the extracted Series (s1) to the console.
Print the Type of the Series:
```
print(type(s1))
```
This prints the type of the Series (s1). The result will show that s1 is a Pandas Series.

For more Practice: Solve these Related Problems:

Write a Pandas program to extract a specific column from a DataFrame as a Series and then rename its index using a custom function.
Write a Pandas program to convert multiple columns of a DataFrame to separate Series and then merge them based on index.
Write a Pandas program to convert a DataFrame's first column to a Series and fill missing values with the column mean.
Write a Pandas program to extract a DataFrame column as a Series and then reverse the order of the Series.

Go to:

Previous: Write a Pandas program to convert a NumPy array to a Pandas series.
Next: Write a Pandas program to convert a given Series to an array.

Python-Pandas Code Editor:

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