CODE EXAMPLE FOR PYTHON

Python find permutations of operators between each digit in a given string of digits will result in a particular answer

from itertools import permutations,combinations_with_replacement
def numbersToTarget(numbers,target,reuseOper=True,allowGroups=True,operators=["+","-","*","/"]):   
    groups      = groupPatterns(len(numbers)) if allowGroups else [ "+".join("X"*len(numbers)) ]
    seen        = set()
    for values in permutations(numbers,len(numbers)):
        for operCombo in combinations_with_replacement(operators,len(numbers)-1) if reuseOper else [operators]:
            for opers in permutations(operCombo,len(numbers)-1):
                formulaKey = str(opers)+str(values)
                if formulaKey in seen: continue # ignore variations on parentheses alone
                for pattern in groups:
                    formula = "".join(o+p      for o,p in zip([""]+list(opers), pattern.split("+")))
                    formula = "".join(str(v)+p for v,p in zip([""]+list(values),formula.split("X")))
                    try:
                        if eval(formula) == target:
                            seen.add(formulaKey)
                            yield formula
                            break 
                    except: pass

for formula in numbersToTarget([9,8,1,2],24):
    print("24 =",formula)
for formula in numbersToTarget([9,8,1,2,5],0,allowGroups=False):
    print("0 =",formula)