how to find unique values in pandas dataframe column

Title: Finding Unique Values in a Pandas DataFrame Column: A Step-by-Step Tutorial
Introduction:
Pandas is a powerful data manipulation library in Python, widely used for working with structured data. One common task is finding unique values in a DataFrame column. In this tutorial, we'll walk through the process of identifying unique values in a specific column using Pandas.
Prerequisites:
Make sure you have Python and Pandas installed on your machine. You can install Pandas using:
Step 1: Import Pandas
Start by importing the Pandas library in your Python script or Jupyter notebook:
Step 2: Create a DataFrame
For this tutorial, let's create a sample DataFrame:
Step 3: Find Unique Values in a Column
Now, let's say we want to find the unique values in the 'City' column. Use the unique() method to achieve this:
This will output:
Step 4: Count the Number of Unique Values
If you also want to know the count of each unique value, you can use the value_counts() method:
This will output:
Conclusion:
In this tutorial, we've demonstrated how to find unique values in a Pandas DataFrame column. The unique() method provides a straightforward way to obtain a list of unique values, while value_counts() allows you to see the frequency of each unique value. This is a fundamental operation when exploring and analyzing data using Pandas.
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