In this tutorial, we will look at how to check if a column in a Pandas dataframe is a category type column or not with the help of some examples.
How to check if a Pandas column is a category column or not?
You can compare the column’s dtype with “category” to check whether a column is a category type column or not in Pandas. The following is the syntax –
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# check if column is a category column df["Col"].dtype == "category" # alternatively, you can also use hasattr() hasattr(df["Col"], "cat")
It returns True
if the column is of category
dtype.
Examples
Let’s look at some examples of using the above methods. First, we will create a sample dataframe that we will be using throughout this tutorial.
import pandas as pd # create a dataframe df = pd.DataFrame({ "Name": ["Tim", "Sarah", "Hasan", "Jyoti", "Jack"], "Shirt Size": ["Small", "Medium", "Large", "Small", "Large"] }) # change to category dtype df["Shirt Size"] = df["Shirt Size"].astype("category") # display the dataframe print(df)
Output:
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Name Shirt Size 0 Tim Small 1 Sarah Medium 2 Hasan Large 3 Jyoti Small 4 Jack Large
We now have a dataframe containing the name and t-shirt size information of some students in a university. Note that in the above code we converted the “Shirt Size” column to category
dtype using the Pandas astype() function.
Check if a column is a Pandas categorical column
Let’s now check whether the “Shirt Size” column is a category type column or not. We use the above syntax to compare the column’s dtype with “category”.
# check if pandas column is of category type print(df["Shirt Size"].dtype == "category")
Output:
True
We get True
as the output indicating that the column is of category
dtype.
Check if a Pandas series contains categorical data using hasattr()
Alternatively, you can also use the Python hasattr()
function to check if a Pandas series contains categorical data or not (which is the same as checking whether it’s a category type column or not).
# check if pandas column is of category type print(hasattr(df["Shirt Size"], "cat"))
Output:
True
Here, we check whether the “Shirt Size” column in the above dataframe has a “cat” attribute. We get True
as the output, indicating that the column has a “cat” attribute and thus is a category type column in Pandas.
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You might also be interested in –
- Get List of Categories in Pandas Category Column
- Pandas – Set Category Order of a Categorical Column
- Pandas – Rename Categories in Category Column
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