Append to array[i] (first element) until compare condition is no longer True

user_17646770 0
Viewed 105

I have two arrays initialized like so:

bins = [['1'], ['2'],...['10']]

tasks = ['1:x', '1:y', '2:x', '2:y', '2:z'.... '10:x', '10:y']

I was trying to iterate through [tasks] and compare the string value before ':' to each element in [bins], and if it matches append tasks[i] to bins[i]. So I am expecting bins to be updated like so:

bins = [[1, 1:x, 1:y]...[10, 10:x, 10:y]]

Then I thought it made sense to split off the content before the ':' in [tasks] to compare effectively, so I split off the contents of [tasks] before the ':' and created a new array:

splits = ['1', '1', '2', '2', .....'10', '10']

Now in my code I am actually iterating through [splits] and trying to append tasks[i] if splits[i] is in bins[i], using the code below:

for i in range(len(splits)):
    if (splits[i] in bins[i]) == True:
        bins[i].extend(tasks[i])

The problem is the code above does not find any matches (never returns a True), and thus bins[i] is not updated.

Am I not iterating through my arrays correctly? Am I not comparing correctly? How can I compare the first element of [bins] to each element of [splits] until it does not match and move onto the next element of bins[i] and repeat?

arrays python
3 Answers

I believe this is happening because you are comparing different datatypes. Bins contains lists of numbers and splits contains strings.

Looking at you're questions, it seems like you want something like this:

for a in enumerate(bins):
    for b in enumerate(splits):
        if bins[a][0] == splits[b]
            bins[a].extend(tasks[b])
  • Calling enumerate is the same as calling range(len(bins))
  • Since the ellements in bins are ints, in lists you want the element on index i and the first (and only element) in the list (if i was 0 that would be bins[0] which is [1] and then [1][0] and 1 is the element on index 0)
user_176469780

You're comparing string against int

>>> '1' in [1]
False
>>> '1' in [str(1)]
True
>>> int('1') in [1]
True

So do the:

int(splits[i])

And it should send true.

Upd. Regarding your correction, though your code should be working, try to make it more pythonic, maybe that will do better.

>>> if ('1' in ['1']) == True:
...     True
... 
True
>>> if ('1' in ['1']) == False:
...     True

... 
>>> if '1' in ['1']:
...    print("do things")
... do things

if splits[i] in bins[i]:
   bins[i].extend(tasks[i])
user_66346350

This code seems to work for me:

for i in range(len(tasks)):
  for j in range(len(bins)):
    if int(tasks[i][0]) in bins[j]:
      bins[j].append(tasks[i])
print(bins)
user_107227390
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