How to Master Python’s applymap for Efficient Data Transformation

1. Introduction

Hello everyone, I am a Python enthusiast. A few days ago a fan named Lee asked a data‑processing question, which I’m sharing here.

The fan had already written a solution that performed well, but the requirement went beyond that.

2. Implementation

A senior contributor first suggested using the applymap() method, as shown in the figure.

The resulting output satisfies the fan’s original requirement.

Later the fan added further requirements, illustrated below.

A straightforward loop traversal can also work, though it takes a bit more time.

Here is a high‑quality code snippet from the senior contributor, shown below.

This code is valuable; a brief introduction follows.

Thus, it perfectly meets the fan’s needs.

3. Conclusion

This article addresses a fan’s question by applying Python tools to perform batch data conversion; it cleverly uses the applymap() function and lambda expressions, helping solve the problem and deepening understanding of the function. Thanks to Lee for the question, to the senior contributor for the ideas and code, and to other participants for their discussion. Two methods are presented, and other solutions are welcome.