Question

My example dictionary is this

data_dictionary = {1:'blue',2:'green',3:'red',4:'orange',5:'purple',6:'mauve'}

The data_dictionary can have more elements depending on the incoming data . The first value is what we call a payload_index. I always get payload_index 1 to 4 .

I need to assemble a list from this. Pretty easy:

for payload_index in data_dictionary :
            assembled_packet.append(data_dictionary[payload_index])

My problem is I need to always skip the 3rd element. I guess I could do an if but that would be inefficient:

for payload_index in data_dictionary :
            if payload_index <> 3:
                assembled_packet.append(data_dictionary[payload_index])

I could do it in two steps and do the first three elements but the problem is I cannot figure out how to get the rest since the number of elements after the 3rd varies. I tried using an impossibly high index (below) but that obviously fails:

#get element 1 and two
for index in range(0,3):
            assembled_packet.append(data_dictionary[index])

#get element 1 and two
for index in range(4,999):
            assembled_packet.append(data_dictionary[index])

Any ideas? Thanks!

Answer 1

inefficient? That seems like a premature optimisation! Just use normal code:

for payload_index in data_dictionary:
    if payload_index != 3:
        assembled_packet.append(data_dictionary[payload_index])

or even better:

assembled_packet = [data_dictionary[index] for index in data_dictionary if index != 3]

Of course, you could just simply do:

>>> d = {1:'blue',2:'green',3:'red',4:'orange',5:'purple',6:'mauve'}
>>> d.pop(3)
'red'
>>> list(d.values())        # in py3k; in python-2.x d.values() would do
['blue', 'green', 'orange', 'purple', 'mauve']

P.S. <> is long since deprecated.