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# -------------
# Cython Syntax
# -------------
# Import statements
import numpy
from numpy cimport abs
# Import statements with selection
import numpy as np
from cython.view cimport array as cvarray
# Extern values
cdef extern from 'foo.h':
int foo_int
struct foo_struct:
pass
# Type definitions
ctypedef int word
# C struct
cdef struct Foo:
pass
# C class
cdef class MyType(ParentType):
cdef int field
cpdef foo(self, x=*, int k=*)
# C class with classmethod
cdef class Blah:
def some_method(self):
print self
some_method = classmethod(some_method)
a = 2*3
print "hi", a
# C function
cpdef fib(int n): # Cython version
"""Print a Fibonacci series up to n."""
cdef unsigned int a = 0
cdef int b
b = 1
while a < n:
print(a)
a, b = b, a+b
# C function with return type
cpdef unsigned int foo():
return 1 + 2
# C function with no GIL
cpdef int sum3d(int[:, :, :] arr) nogil:
cdef size_t i, j, k, I, J, K
cdef int total = 0
cdef:
int I, J, K
I = arr.shape[0]
J = arr.shape[1]
K = arr.shape[2]
for i in range(I):
for j in range(J):
for k in range(K):
total += arr[i, j, k]
return total
# Inline C function
cdef inline int something_fast(int a, int b):
return a*a + b
# Python function with typed parameters
def foo(int n)
return n + 1
# Assignment on declaration
cdef int n = python_call(foo(x,y), a + b + c) - 32
cdef int [:, :, :] narr_view = narr
# Definition with C-block syntax
cdef:
int carr[3][3][3]
int [:, :, :] carr_view = carr
# Iteration with steps
for i from 0 <= i < 10 by 2:
print i
# -------------
# Python syntax
# -------------
# Function call
print("NumPy sum of the NumPy array before assignments: %s" % narr.sum())
# Assignment
narr = np.arange(27, dtype=np.dtype("i")).reshape((3, 3, 3))
carr_view[...] = narr_view
cyarr_view[:] = narr_view
narr_view[:, :, :] = 3
carr_view[0, 0, 0] = 100
# Equality test
1 + 1 == 2
1 < 2
# For loops
for i in range(i]:
total = total + 1
# Function definition
def fib(n): # Python version
"""Print a Fibonacci series up to n."""
a, b = 0, 1
while a < n:
print a,
a, b = b, a+b
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