Remove Lines from a Tab File According to Conditions in Another Tab File Using Python with Pandas Library

Converting Arrays for Plotting with Matplotlib: A Guide to Reshaping and Visualizing Data in Python

Grouping Dates in Pandas: A Step-by-Step Guide for Efficient Time Series Data Analysis

Replacing Missing Values with Interpolation in Pandas DataFrames

Mapping Values from One Column Based on Condition in Pandas Dataframe

Summing Hourly Values Between Two Dates in Pandas Using GroupBy Operation

Working with Multi-Column DataFrames in Pandas: A Deep Dive into Advanced Manipulation Techniques for Efficient Data Analysis

Calculating and Storing Fractional Difference Between Consecutive Rows in a Pandas DataFrame

Building a Custom Dictionary from a JSON File Using Python

To calculate the sum of sales for each salesman in a month before their training date, we need to group by "salesman" and "transaction_month", then apply the aggregation function `sum` to the 'sales' column.