CODEWITHSUNDEEP
pythonpython-3.xpython-exec
user447586
user447586

Reputation: 186

python3 print() in exec()

In python3, when I run

>>> exec("","","")
TypeError: exec() arg 2 must be a dict, not str
>>> exec( "print('Hello')", print("World"), print("!") )
World
!
Hello
>>> type(print("World"))
World
<class 'NoneType'>

I mean in the Python3, the arg2 of exec() expects a dict, but we can still put a print() function which is not a dict. why?

Upvotes: 2

Views: 397

Answers (2)

Fernando Jorge Mota
Fernando Jorge Mota

Reputation: 1554

Simple!

It's acceptable because its value is None (it can accept None or a dict), which is the default value for the argument.

In a example, a call such as:

exec("print('Hello')")

Is the same as:

exec("print('Hello')", None, None)

Upvotes: 7

user1726343
user1726343

Reputation:

print returns None, which is a valid argument for an optional parameter.

Upvotes: 3

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