Question

f = open("sonad.txt",encoding="utf-8")
c = f.readlines()
blokk = [[]] * 15
for read in c:
    length = len(read.strip())
    blokk[length].append(read.strip())

sonad.txt has just some random words and I would like to put them in an order like so:

All the words, that are 1 letter long go to blokk[1]
2 letters long go to blokk[2]
And so on…

But what my current code does is that it adds an element to allL block[x] so that
blokk[1] blokk[2] blokk[3] ….. are all the same.

Answer 1

The line blokk = [[]] * 15 creates a list that has the same empty list in it 15 times.

You want to use a list comprehension instead:

blokk = [[] for _ in range(15)]

Try it out for yourself:

>>> blokk = [[]]*15
>>> blokk
[[], [], [], [], [], [], [], [], [], [], [], [], [], [], []]
>>> blokk[0].append(1)
>>> blokk
[[1], [1], [1], [1], [1], [1], [1], [1], [1], [1], [1], [1], [1], [1], [1]]
>>> blokk = [[] for _ in range(15)]
>>> blokk
[[], [], [], [], [], [], [], [], [], [], [], [], [], [], []]
>>> blokk[0].append(1)
>>> blokk
[[1], [], [], [], [], [], [], [], [], [], [], [], [], [], []]