numba - TypingError: cannot determine Numba type of <class 'builtin_function_or_method'>

Question

I have a simple function to rank poker hands (the hands are strings).

I call it with rA,rB = rank(a),rank(b) and here is my implementation. Works well without @jit(nopython=True), but with it, it fails:

   File "C:/Users/avi_na/Desktop/poker.py", line 190, in <module>
        rA,rB = rank(a),rank(b)

      File "C:\Continuum\anaconda3\lib\site-packages\numba\dispatcher.py", line 344, in _compile_for_args
        reraise(type(e), e, None)

      File "C:\Continuum\anaconda3\lib\site-packages\numba\six.py", line 658, in reraise
        raise value.with_traceback(tb)

TypingError: cannot determine Numba type of <class 'builtin_function_or_method'>

---

from numba import jit
from numba.types import string

@jit(nopython=True)
def rank(hand):
#    assert(len(hand) == 5)
    rank = "N/A"

    p = pd.Series([h[0] for h in hand]).value_counts()
    v = sorted(set(pd.Series([h[0] for h in hand]).values), reverse=True)
    s = sorted(hand, key=lambda k:k[0])    
    z = zip(s,s[1:])

    if all(x[0]==y[0]-1 for x,y in z):
        rank = "Straight "

    if len(set([h[1] for h in hand])) == 1:
        rank += "Flush "

    if "Straight Flush" in rank and sum([h[0] for h in hand]) == sum([10,11,12,13,14]):
        rank = "Royal Flush"

    elif p[p.idxmax()] == 4:
        rank = "4 Of A Kind : %d" % p.idxmax()

    elif p[p.idxmax()] == 3 and p[p.idxmin()] == 1:
        rank = "3 Of A Kind : %d" % p.idxmax()

    elif p[p.idxmax()] == 3 and p[p.idxmin()] == 2:
        rank = "Full House : %d,%d" % (p.idxmax(), p.idxmin())

    elif p[p.idxmax()] == 2:
        max2 = p.nlargest(2)

        if list(max2) == [2,2]:
            max2 = sorted(list(max2.keys()), reverse=True)
            rank = "2 Pairs : %d,%d" % (max2[0],max2[1])
        else:
            rank = "Pair : %d" % p.idxmax()

    else:
        rank = "High Card : %d" % v[0]


    return rank

Answer 1

Pandas and several other function calls in your code will not work with nopython=True. The available libraries that can be used with numba jit in nopython is fairly limited (pretty much only to numpy arrays and certain python builtin libraries). You can find more information here