How to check if a return object is a dictionary in python

Question

I have written a function f(x) that either returns a dictionary or an error message.

def myfunc():
    try:
       return dictionary
    except BaseException as e:
       return e

return_value = myfunc()

if return_value a dictionary:
    do this
else:
    do that

I need to detect the type of return in another function f(y) which calls f(x).

How do I do that?

thanks in advance

Not pretty sure about this, but I guess you can just to `try ... catch` outside `myfunc()`, since on error the function will pass the exception to the caller. — j1-lee, Nov 15 '21 at 02:01
@j1-lee: The exception is not propagated outside of `myfunc()`. — President James K. Polk, Nov 15 '21 at 02:02
You should not `return` an exception instance. You should just let it be raised. That's *the point* of how exceptions work. — Karl Knechtel, Nov 15 '21 at 02:21

score 3 · Accepted Answer · answered Nov 15 '21 at 02:02

3

Your example does not follow normal best practices, but you would do the following:

if type(return_value) is dict:

or

if isinstance(return_value, dict):

answered Nov 15 '21 at 02:02

Cresht

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score 2 · Answer 2 · answered Nov 15 '21 at 02:01

2

isinstance(return_value, dict)

answered Nov 15 '21 at 02:01

ramwin

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score 1 · Answer 3 · answered Nov 15 '21 at 02:02

1

You can check a value's type as follows:

if type(return_value) == dict:
    print("It is a dictionary.")
else:
    pinrt("It is not a dictionary")

There are several ways to check a type of value, see: How to check if type of a variable is string?

answered Nov 15 '21 at 02:02

Park

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score 0 · Answer 4 · answered Nov 15 '21 at 02:08

An alternative is to return a tuple that keeps track of whether there was an error:

def myfunc():
    try:
       return (True, dictionary)
    except BaseException as e:
        return (False, e)

was_successful, return_value = myfunc()

if was_successful:
    do this
else:
    do that

How to check if a return object is a dictionary in python

4 Answers4