Lesson 33 of 55
9 mins readPython Code Evaluation: eval() & Scoping Rules
In Plain English
eval(expr) executes an expression tree in the global scope of the current module, generating new functions, types, and constants dynamically at runtime.
Deep Dive: How It Works
Global Scope: eval() always evaluates expressions in the global module scope, not inside the local function frame where eval is called.
Programmatic Code Generation: Generate hundreds of specialized mathematical functions in a loop with eval.
Core Rules to Remember
Global Evaluation: Evaluates expressions within the active module environment.
Code Generation Loops: Automate boilerplate method generation for multiple operators.
Live Interactive Example
Hit Run Code to see it liveDynamic Function Generation with eval
Python 3.12
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Output Console
Click "Run Code" to view the rendered output.
How it works: eval dynamically created 3 top-level compiled functions from a single loop.
Your Turn: Micro Challenge
No pressure! Edit the starter code below and test your solution with instant feedback.
Micro Exercise
Generate Dynamic Constant with eval
- Use `eval(:( ZEN_CONSTANT = 999 ))`.
- Print `"Constant: $ZEN_CONSTANT"`.
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Sandbox Output
Click "Run & Check" to test your solution.
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