What is L1 regularization?

Updated May 15, 2026

Short answer

L1 adds absolute value penalty to cost function.

Deep explanation

Encourages sparsity by forcing some weights to zero.

Real-world example

Feature selection in high-dimensional datasets.

Common mistakes

  • Assuming it behaves like L2 regularization.

Follow-up questions

  • Why does L1 create sparsity?
  • Where is it used?

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