String in Cython functions

问题:

I'd like to do this to pass a string to a Cython code:

# test.py
s = "Bonjour"
myfunc(s)

# test.pyx
def myfunc(char *mystr):
    cdef int i
    for i in range(len(mystr)):           # error! len(mystr) is not the length of string
        print mystr[i]                    # but the length of the *pointer*, ie useless!

but as shown in comment, here it doesn't work as expected.

---

The only workaround I've found is passing also the length as parameter of myfunc. Is it correct? Is it really the simplest way to pass a string to a Cython code?

# test.py
s = "Bonjour"
myfunc(s, len(s))


# test.pyx
def myfunc(char *mystr, int length):
    cdef int i
    for i in range(length):  
        print mystr[i]       

回答1:

The simplest, recommended way is to just take the argument as a Python string:

def myfunc(str mystr):