Perfrom cumulative sum over a column but reset to 0 if sum become negative in Pandas
Slightly modify also this method is slow that numba
solution
sumlm = np.frompyfunc(lambda a,b: 0 if a+b < 0 else a+b,2,1)
newx=sumlm.accumulate(df.Value.values, dtype=np.object)
newx
Out[147]: array([7, 9, 3, 0, 8, 8], dtype=object)
numba
solution
from numba import njit
@njit
def cumli(x, lim):
total = 0
result = []
for i, y in enumerate(x):
total += y
if total < lim:
total = 0
result.append(total)
return result
cumli(df.Value.values,0)
Out[166]: [7, 9, 3, 0, 8, 8]