How to convert a string to python code in python?

Question

If I have a string containing some code in a python file. I want to run the code in the string, for example:

program = "for i in range(100):\n\tprint(i)"
eval(program)

However, I'm pretty sure eval only works for mathematical operations, so it throws a syntax error:

Traceback (most recent call last):
  File "main.py", line 2, in <module>
    eval(program)
  File "<string>", line 1
    for i in range(100):
      ^
SyntaxError: invalid syntax

Is there a way in python of running code contained in a string?

Strictly speaking, the answer to the question in the title is to use `compile`; `exec` produces the code *and* executes it. — chepner, Dec 02 '19 at 16:57
possible duplicate: https://stackoverflow.com/questions/701802/how-do-i-execute-a-string-containing-python-code-in-python — natka_m, Dec 02 '19 at 16:58

score 6 · Accepted Answer · answered Dec 02 '19 at 16:55

6

Yes, eval() only evaluates expressions, not statements or suites (which comprise full Python programs).

You're looking for the exec() function.

exec("for i in range(100):\n\tprint(i)")

However, do remember you usually don't need eval() or exec(), and especially you'll never want to exec() or eval() user input.

answered Dec 02 '19 at 16:55

AKX

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this is clearly a duplicate. you've been around long enough to know to mark it as one... – wpercy Dec 02 '19 at 16:56

Joshua Schlichting · Answer 2 · 2019-12-02T17:45:38.887

0

Use the exec() function.

program = "for i in range(100):\n\tprint(i)"
exec(program)

edited Dec 02 '19 at 17:45

answered Dec 02 '19 at 16:56

Joshua Schlichting

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How to convert a string to python code in python?

2 Answers2