Pandas Get First Column of DataFrame as Series?

We can get the first column of pandas DataFrame as a Series by using iloc[], columns[], and head() function. In this article, I will explain how to get the first columns of DataFrame as a series with several examples.

1. Quick Examples of Getting First Column as a Series

If you are in a hurry below are some quick examples of getting the first column as a Series.

# Below are quick examples.

# Example 1: use DataFrame.iloc[] 
# To get first column as a series
df2 = df.iloc[:, 0]

# Example 2: use columns[] 
# To get first column as a series
df2 = df[df.columns[0]]

# Example 3: use column name 
# To get first column as a series
df2 = df.Courses

# Example 4: use head() function 
# To get first column as a series
df2 = df.T.head(1).T

2. Create Pandas DataFrame

Let’s create a Pandas DataFrame from a Python dictionary in which keys are 'Courses', 'Fee', 'Duration' and 'Discount‘, and values are taken as a list of corresponding key values.

import pandas as pd
technologies = {
    'Courses':["Spark","PySpark","Hadoop","Python","PySpark"],
    'Fee' :[20000,25000,26000,22000,24000],
    'Duration':['30days','40days','35days','40days','60days'],
    'Discount':[1000,2300,1200,2500,2000]
              }
df = pd.DataFrame(technologies)
print("Create DataFrame:\n", df)

Yields below output.

3. Get the First Column as a Series

In pandas, each column is represented as a Series hence it is very easy to get the first column of pandas DataFrame as a Series by using the iloc[] property. Use df.iloc[:,0] to get the first column as a Series. For example.

# Get first column as a series
df2 = df.iloc[:, 0]
print("After getting the first column of DataFrame as a series:\n", df2)

Yields below output.

4. Use df[] to Get the First Column as a Series

When we use df[df.columns[i]] function for extracting the first column of DataFrame, it will return the column based on the label associated with the index. Here, df.columns[0] returns the label of the first column of DataFrame, and df[‘label’] returns the column as a Series.

# Get first column as a series
df2 = df[df.columns[0]]
print("After getting the first column of DataFrame as a series:\n", df2)

Yields the same output as above. We can also use the column name to extract the first column as a series. For examples.

# Use column name to get first column as a series
df2 = df.Courses
print("After getting the first column of DataFrame as a series:\n", df2)

Yields the same output as above.

5. Use head() to Get First Column of Pandas DataFrame

We can also use df.T.head(1).T to get the first column of pandas DataFrame as a Series.

# Use head() function to get first column as a series
df2 = df.T.head(1).T
print("After getting the first column of DataFrame as a series:\n", df2)

Yields below output.

# Output:
# After getting the first column of DataFrame as a series:
   Courses
0    Spark
1  PySpark
2   Hadoop
3   Python
4  PySpark

6. Complete Example

import pandas as pd
technologies = {
    'Courses':["Spark","PySpark","Hadoop","Python","PySpark"],
    'Fee' :[20000,25000,26000,22000,24000],
    'Duration':['30days','40days','35days','40days','60days'],
    'Discount':[1000,2300,1200,2500,2000]
              }
df = pd.DataFrame(technologies)
print(df)

# Use DataFrame.iloc[] to get first column as a series
df2 = df.iloc[:, 0]
print(df2)

# Use columns[] to get first column as a series
df2 = df[df.columns[0]]
print(df2)

# Use column name to get first column as a series
df2 = df.Courses
print(df2)

# Use head() function to get first column as a series
df2 = df.T.head(1).T
print(df2)

Frequently Asked Questions of Get First Column of DataFrame as Series

7. Conclusion

In this article, I have explained how to get the first column of pandas DataFrame as a Series by using DataFrame.iloc[], DataFrame.columns[], and head() function with examples.

Happy Learning !!

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• Create a Set From a Series in Pandas
• Remove NaN From Pandas Series
• Pandas Series filter() Function
• Pandas Series loc[] Function
• Pandas Iterate Over Series
• Pandas explode multiple columns of DataFrame

References

• https://pandas.pydata.org/docs/reference/api/pandas.Series.html