TypeError: cannot unpack non-iterable int objec

Question

how can I solve this error After running my code as follows . I am using the function below and implementin running window for loop on it but end up getting the error below. The for loop works and hungs at a point.

def get_grps(s, thresh=-1, Nmin=3):
    """
    Nmin : int > 0
    Min number of consecutive values below threshold.
    """
    m = np.logical_and.reduce([s.shift(-i).le(thresh) for i in range(Nmin)])
    if Nmin > 1:
        m = pd.Series(m, index=s.index).replace({False: np.NaN}).ffill(limit=Nmin - 1).fillna(False)
    else:
        m = pd.Series(m, index=s.index)

    # Form consecutive groups
    gps = m.ne(m.shift(1)).cumsum().where(m)

    # Return None if no groups, else the aggregations
    if gps.isnull().all():
        return 0
    else:
        agg = s.groupby(gps).agg([list, sum, 'size']).reset_index(drop=True)
        # agg2 = s2.groupby(gps).agg([list, sum, 'size']).reset_index(drop=True)
        return agg, gps


data_spi = [-0.32361498 -0.5229471   0.15702732  0.28753752   -0.01069884 -0.8163699
  -1.3169327   0.4413181   0.75815576  1.3858147   0.49990863-0.06357133
-0.78432    -0.95337325 -1.663739    0.18965477  0.81183237   0.8360347
  0.99537593 -0.12197364 -0.31432647 -2.0865853   0.2084263    0.13332903
 -0.05270813 -1.0090573  -1.6578217  -1.2969246  -0.70916456   0.70059913
 -1.2127264  -0.659762   -1.1612778  -2.1216285  -0.8054617    -0.6293912
 -2.2103117  -1.9373081  -2.530625   -2.4089663  -1.950846    -1.6129876]
lon = data_spi.lon
lat = data_spi.lat
print(len(data_spi))

n=6

for x in range(len(lat)):
    for y in range(len(lon)):
        if data_spi[0, x, y] != 0:
            for i in range(len(data_spi)-70):
                ts = data_spi[i:i+10, x, y].fillna(1)
                print(ts)
                # print(np.array(ts))

                agg, gps = get_grps(pd.Series(ts), thresh=-1, Nmin=3)

                duration = np.nanmean(agg['sum'])
                frequency = len(agg['sum'])
                severity = np.abs(np.mean(agg['sum']))
                intensity = np.mean(np.abs(agg['sum'] / agg['size']))
                print(f'intensity {intensity}')

I get this error

 Traceback (most recent call last):
 File "/Users/mada0007/PycharmProjects/Research_ass /FREQ_MEAN_INT_DUR_CORR.py", line 80, in <module>
 agg, gps = get_grps(pd.Series(ts), thresh=-1, Nmin=3)
 typeError: cannot unpack non-iterable int object

How can I resolve this error ?

Answer 1

Just replace return 0 by return 0, 0, or better: raise an error instead of returning 0

When your if condition is True, you only return 0. Then later, when you do agg, gps = get_grps(...), you tell python to unpack the result of the function. Then, python is expecting a 2-length iterable, and try to unpack it, but as it says: it 'cannot unpack non-iterable int object'...

So a quick workaround is to return a tuple (0, 0) with return 0, 0, but it is quite bad because you return integers where objects are expected. your script will crash on the next line duration = np.nanmean(agg['sum']) (since agg is 0).

Some cleaner solutions to handle this case would be to unpack in a second time:

def get_grps(s, thresh=-1, Nmin=3):
    # ...
    if gps.isnull().all():
        return None
    else:
        # ...
        return agg, gps

for i in range(len(data_spi)-70):
    ts = data_spi[i:i+10, x, y].fillna(1)

    result = get_grps(pd.Series(ts), thresh=-1, Nmin=3)
    if result is None:
        break

    agg, gps = result

    duration = np.nanmean(agg['sum'])
    frequency = len(agg['sum'])