CODEWITHSUNDEEP
pythonarrays
cah
cah

Reputation: 149

turning an array of list indeces into a 2d array of 0s with a 1 at correct index

def cluster_guess_for_each_obs(self):
    flat_cluster_guess = [self.argmax_list(cp) for cp in self.cluster_possibilities_for_observations()]
    zero_cluster = [0.0 for i in self.clusters]
    all_zero_clusters = [zero_cluster for p in range(len(flat_cluster_guess))]
    for enum in enumerate(flat_cluster_guess):
        all_zero_clusters[enum[0]][enum[1]] = 1.0
    print all_zero_clusters
    self.cluster_assignments = all_zero_cluster 
    return

Now the first line returns a list of 0s and 1s representing which cluster each data belongs to. I would like to convert this (ex.[0, 1, 0, 0, 1, 1, 1]) into a an array of arrays of length two which looks like this for above: [[1, 0], [0, 1], [1, 0], [1, 0], [0, 1], [0, 1], [0, 1]]. What I'm getting instead is after the first few enumeration it is all 1s.

Not sure what I'm doing wrong.

Upvotes: 0

Views: 60

Answers (3)

David Robinson
David Robinson

Reputation: 78600

This line doesn't do what you think it does:

all_zero_clusters = [zero_cluster for p in range(len(flat_cluster_guess))]

It repeats the same list (not copies of the list- pointers to the same exact list) len(flat_cluster_guess) times. That means that when you change one item in the list, you change all of them.

Instead, move the expression [0.0 for i in self.clusters] into the list comprehension, like this:

all_zero_clusters = [[0.0 for i in self.clusters] for p in range(len(flat_cluster_guess))]

or

all_zero_clusters = [[0] * len(self.clusters) for p in range(len(flat_cluster_guess))]

Upvotes: 1

mVChr
mVChr

Reputation: 50185

flat = [0, 1, 0, 0, 1, 1, 1]
cluster = []
for pos in flat:
    n = [0, 0]
    n[pos] = 1
    cluster.append(n)
print cluster
# [[1, 0], [0, 1], [1, 0], [1, 0], [0, 1], [0, 1], [0, 1]]

Upvotes: 1

john_science
john_science

Reputation: 6551

Okay, if I understand you correctly, you just need to implement a method that does this and call it once:

guess = [0, 1, 0, 0, 1, 1, 1]

def build_array(guess):
    result = []

    for i in range(len(guess)):
        new_result.append([0,0])

    for i in range(len(result)):
        result[i][guess[i]] = 1

    return result

Here I have chosen a solution that is more readable than 'Pythonic'. But hopefully this makes the basic logic you need to implement clear.

Upvotes: 1

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