CODEWITHSUNDEEP
cython
schoon
schoon

Reputation: 3334

Why can I not use int parameter in Cython in Jupyterlab?

I am trying to use Cython in Jupyterlab:

%load_ext Cython
%%cython -a
    
def add (int x, int y):
    cdef int result
    result = x + y
    return result
add(3,67)

error:

File "<ipython-input-1-e496e2665826>", line 9
    def add (int x, int y):
                 ^
SyntaxError: invalid syntax

What am I missing?

Upvotes: 2

Views: 285

Answers (2)

Peter Badida
Peter Badida

Reputation: 12189

Update:

I just measured cpdef vs def and the difference between score was quite a low one (45(cpdef) vs 52(def), smaller = better/faster), so for your function it might not matter if called just a few times, but having that chew through a large amount of data might do some real difference.

If that's not applicable for you, just call that %load_ext in a separate cell, keep def and that should be enough.

(Cython 0.29.24, GCC 9.3.0, x86_64)

Use cpdef to make it C-like function, but also to expose it to Python, so you can call it from Jupyter (because Jupyter is using Python, unless specified by the %%cython magic func). Also, check the Early Binding for Speed section.

cpdef add (int x, int y):
    cdef int result
    result = x + y
    return result

Also make sure to check Using the Jupyter notebook which explains that the % needs to be in a separate cell as ead mentioned in the comments.

Upvotes: 3

chepner
chepner

Reputation: 532093

add has to be defined with cdef, not def.

cdef add (int x, int y):
    cdef int result
    result = x + y
    return result
add(3,67)

Upvotes: -1

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