KeyError when accessing DataFrame with data from Excel

Question

I am running into a KeyError which I don't understand.

This is my code:

print(PERIODS)
print(PRODUCTS, '\n')
print(production, '\n')
print(demand, '\n')
SETUP_ITEMS = [[] for t in PERIODS]
for t in PERIODS:
    print("\n t =", t)
    for k in PRODUCTS:
        print("k =", k)
        if production[k][t]==(max(0,demand[k][t]-stock[k][t])) > 0:
            SETUP_ITEMS[t].append(k)
print(SETUP_ITEMS)

This is the ouput:

range(1, 7)
range(1, 3) 

     1   2   3   4   5   6
1  110  49   0  82  40  65
2   48  75  15  10  15  70 

     1   2   3   4   5   6
1  110  49   0  82  40  65
2   48  75  15  10  15  70 


 t = 1
k = 1
k = 2

 t = 2
k = 1
k = 2

 t = 3
k = 1
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-35-8b6f312053ac> in <module>()
      8     for k in PRODUCTS:
      9         print("k =", k)
---> 10         if production[k][t]==(max(0,demand[k][t]-stock[k][t])) > 0:
     11             SETUP_ITEMS[t].append(k)
     12 print(SETUP_ITEMS)

/Users/frederic/anaconda/lib/python3.6/site-packages/pandas/core/series.py in __getitem__(self, key)
    599         key = com._apply_if_callable(key, self)
    600         try:
--> 601             result = self.index.get_value(self, key)
    602 
    603             if not is_scalar(result):

/Users/frederic/anaconda/lib/python3.6/site-packages/pandas/core/indexes/base.py in get_value(self, series, key)
   2426         try:
   2427             return self._engine.get_value(s, k,
-> 2428                                           tz=getattr(series.dtype, 'tz', None))
   2429         except KeyError as e1:
   2430             if len(self) > 0 and self.inferred_type in ['integer', 'boolean']:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value (pandas/_libs/index.c:4363)()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value (pandas/_libs/index.c:4046)()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc (pandas/_libs/index.c:5085)()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item (pandas/_libs/hashtable.c:13913)()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item (pandas/_libs/hashtable.c:13857)()

KeyError: 3

I have put all the print commands in there, so you understand the data basis and so that I can see where the loop crashes.

demand is equal to production at this point but production will be manipulated later in the code, so I need this separation.

The data for PERIODS, PRODUCTS, demand, etc. is coming from an Excel file (via openpyxl and pandas). I had this portion of code before, but without that linkage to Excel and not having the other variables as DataFrames (the ranges were 0-based then). It worked fine then. Can somebody explain me what the problem is here? I am trying for a couple of hours and my brain slowly starts to melt. (-:

What I want as an output, is t lists that contain all kproducts where the condition is met.

Thanks!