The pandas library provides powerful methods to quickly summarize and analyze tabular data, such as gene count tables. Here is how the sum, mean, and median methods work, especially when using the axis parameter:

• sum: Calculates the sum of values along a specified axis. Use axis=1 to sum across columns (totals for each row/gene) and axis=0 to sum across rows (totals for each column/sample);
• mean: Computes the average value along a given axis. Use axis=1 for the mean across samples for each gene, or axis=0 for the mean across genes for each sample;
• median: Finds the median value along a specified axis. Use axis=1 for the median across samples for each gene, or axis=0 for the median across genes for each sample.

For example, counts_df.sum(axis=1) returns the total counts for each gene by summing values across all samples. Setting axis=0 instead returns totals for each sample by summing across all genes. The same logic applies for mean and median. This flexibility allows you to easily calculate summary statistics for either genes or samples in your dataset.