juancarlospaco/Cython_CheatSheet.md

## Cython_CheatSheet.md

      
    Raw
  

              Cython_CheatSheet.md
            
          
    Python 3 to Cython CheatSheet

Python 3.7+ to Cython CheatSheet by examples as simple as posible, because I cant find a Cython Cheatsheet on Internet.
It start with simple stuff and continues towards more complex ones, is compatible with PXD that allows to left the *.py untouched.
All values and variable names are example values.
Integers

Python (Medium Integers)
a = 1
Cython (Medium Integers)
cdef int a
a = 1
Nim + NimPy (Medium Integers)
var a = 1
Nim can make it explicit int32() if you want, but is not needed.

Python (Big Integers)
a = 1000000000000000000
Cython (Big Integers)
cdef longlong a
a = 1000000000000000000
Nim + NimPy (Big Integers)
var a = 1000000000000000000
Nim can make it explicit int64() if you want, but is not needed.
Strings

Python
a = "foo"
Cython
cdef char* a
a = "foo"
Nim + NimPy
var a = "foo"
Floats

Python (Small Floats)
a = 1.0
Cython (Small Floats)
cdef double a
a = 1.0
Nim + NimPy (Small Floats)
var a = 1.0

Python (Medium Floats)
a = 1.000001
Cython (Medium Floats)
cdef long double a
a = 1.000001
Nim + NimPy (Medium Floats)
var a = 1.000001

Python (Big Floats)
a = 1.0000000001
Cython (Big Floats)
cdef longlong double a
a = 1.0000000001
Nim + NimPy (Big Floats)
var a = 1.0000000001
Booleans

Python
a = True
Cython
cdef bint a
a = True
Nim + NimPy
var a = true
Functions

Python
def foo(bar: str, baz: bool) -> int:
    return 1
Cython
cdef int foo(char bar, bint baz)
Nim + NimPy
proc foo(bar: string, baz: bool): int =
    return 1
Methods

Python
def foo(self, bar: str, baz: bool) -> int:
    return 1
Cython
cdef int foo(self, char bar, bint baz)
Nim + NimPy
proc foo(self: ObjectHere, bar: string, baz: bool): int =
    return 1
Lambdas

Python
from typing import Callable

variable: Callable[[int, int], int] = lambda var1, var2: var1 + var2
Nim + NimPy
( proc(var1, var2: int): int = var1 + var2 )
Python Lambdas are not supported on Cython. Documentation is missing on Cython.
For Python you are forced to put it on a variable for Type Annotations, Nim anonymous functions are Typed by itself.
Python Lambda syntax is different, Nim anonymous functions are just functions without name.
Classes

Python
class MyObject(object):
  """ Documentation String """
  pass
Cython

Nim + NimPy
type MyObject = object  ## Documentation String
Comments & DocStrings

Python
# This is a comment

""" This is a DocString, plain-text by default """
Cython
# This is a comment

""" This is a DocString, plain-text by default, but Cython itself dont take care about them, you need third party tool """
Nim + NimPy
# This is a comment

## This is a Documentation Comment, **MarkDown** or *ReSTructuredText*, can generate HTML, LaTex, JSON documentation by itself, no third party tool required
Nimpy puts Documentation Comments on the __doc__ as expected.