We can get the first column of pandas DataFrame as a Series by using iloc[], columns[], and head() function. In this pandas article, we can see 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 how to get 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 create DataFrame from 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(df)
Yields below output.
Courses Fee Duration Discount
0 Spark 20000 30days 1000
1 PySpark 25000 40days 2300
2 Hadoop 26000 35days 1200
3 Python 22000 40days 2500
4 PySpark 24000 60days 2000
3. Get 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 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(df2)
Yields below output.
# Output
0 Spark
1 PySpark
2 Hadoop
3 Python
4 PySpark
Name: Courses, dtype: object
4. Use df[] to Get 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(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(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(df2)
Yields below output.
# Output
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)
7. Conclusion
In this article, I have explained how to get first column of pandas DataFrame as a Series using DataFrame.iloc[], DataFrame.columns[], and head() function with examples.
Happy Learning !!
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