Pandas sum unique values in column. query() method.

Pandas sum unique values in column. In the next example we will define a function which will compute the NaN values in each group: May 20, 2019 · I'm trying to add a new column with the sum of the values of another column, but only for distinct rows. unique ()method returns a NumPy array. Method 2: Using Boolean Indexing Boolean indexing is another effective way of filtering rows in a DataFrame. It can be used to sum values along either the index (rows) or columns, while also providing flexibility in handling missing (NaN) values. Apr 3, 2025 · This tutorial explains how to find all unique values in one or more columns in a pandas DataFrame in Python. For a single column, we can sum in two ways: use Python's built-in sum() function and use pandas' sum() method. Just noticed that 'sum' gives me doubled values. I'm trying to obtain this result: col1 col2 Jul 11, 2025 · In Pandas, retrieving unique values from DataFrame is used for analyzing categorical data or identifying duplicates. nunique and I can sum the BUDGET column, but if I sum also the QUANTITY column I will obviously sum up more than I want. To count them, apply len ()to the result. Jul 13, 2018 · I have a data frame of Column1 Column2 1 20 2 25 3 30 2 40 4 18 1 24 and I want to sum Column2 based on the unique values of Column1. unique ()to get all unique values in a column. If I remove margins_name, 'All' column has correct sum value, and 'sum' column seems to add it to rest of values. nunique() is also available as a method on DataFrame. We can Aug 29, 2021 · In this article, you can find the list of the available aggregation functions for groupby in Pandas: count / nunique – non-null values / count number of unique values min / max – minimum/maximum first / last - return first or last value per group unique - all unique values from the group std – standard deviation sum – sum of values mean / median / mode – mean/median/mode var Jul 11, 2025 · DataFrame. Feb 22, 2025 · How to Find Unique Values in a Pandas DataFrame? If you think you need to spend $2,000 on a 120-day program to become a data scientist, then listen to me for a minute. This article depicts how the count of unique values of some attribute in a data frame can be retrieved using Pandas. You might need to sum values in one column only for rows where another column meets specific criteria, or where multiple conditions across different columns are satisfied. Pandas provides powerful and concise ways to achieve this using boolean indexing and the DataFrame. Calculating conditional sums in a Pandas DataFrame is a frequent operation in data analysis. Jan 19, 2024 · This article explains how to get unique values and their counts in a column (= Series) of a DataFrame in pandas. Aug 29, 2021 · It's possible in Pandas to define your own aggfunc and use it with a groupby method. sum () function in Pandas allows users to compute the sum of values along a specified axis. Dec 2, 2021 · This tutorial explains how to sum specific columns in a pandas DataFrame, including several examples. Apr 27, 2024 · Pandas offers several methods to accomplish this, such as value_counts() and groupby(). Nov 7, 2017 · The problem here is I can aggregate CODE with pd. Let's learn how to get unique values from a column in Pandas DataFrame. Jul 23, 2025 · Here, we can count the unique values in Pandas groupby object using different methods. The value_counts() method allows us to count the occurrences of unique values in a column, while the groupby() method enables grouping data by one or more columns and applying counting operations. Series. Apr 12, 2024 · A step-by-step illustrated guide on how to sum the values in a DataFrame column that match a condition in multiple ways. It uses an array of Boolean values to select rows Jun 19, 2019 · Wow, that was fast :) I changed the column and index pd. Get the Unique Values of Pandas using unique () The. It should be noted that pandas' method is optimized and much faster than Python's sum(). Mar 5, 2024 · This code filters the DataFrame df for rows where the ‘Date’ column matches ‘2023-01-02’. It then selects the ‘Sales’ column of these rows and applies the sum() function to calculate the total sales for that specific date. Say we have this dataframe: col1 col2 vote 0 a 2 5 1 a 2 5 2 b 2 2 3 c 4 1 4 d 3 5 5 d 3 5 6 d 3 5 I want to group by col2, and then sum all the votes of distinct pairs of col1 and col 2 (the vote is always the same for each pair of col1 and col2. Use the unique(), value_counts(), and nunique() methods on Series. Example: Nov 12, 2024 · How to count the unique values of a column in Pandas DataFrame? – When working on machine learning or data analysis with Pandas we are often required to get the count of unique or distinct values from a single column or multiple columns. Jul 15, 2025 · Let's discuss how to count distinct values of a Pandas DataFrame column. You can use pd. This method is useful when you want distinct values and their count. pivot_table (df, index='signal', columns='location', aggfunc='size') is it possible to remove the NaN or replace by 0?. query() method. 2nij znfl hehqi umrbfo fxc7 mejll dx1xu mafglda4 bjehw ewnc