在 Python 中将一个数组拆分为另一个数组

Question

I am trying to write a code that compares two arrays ('a' and 'b)' and do something like that, getting the 'c' array:

a = [1, 2, 2, 3, 3, 5]

b = [1, 2, 3] (It is taken from 'a' randomly)

c = [2, 3, 5]

The problem I have is very simple since the algorithm is ok. The code I am using is:

vetor1 = [1, 2, 2, 3, 3, 5]
vetor2 = sorted(random.sample(vetor1, 3))
inter = np.intersect1d(vetor1, vetor2)

cont_array2 = []
for i in range(len(inter)):
    cont2 = 0
    for j in range(len(vetor2)):
        if inter[i]==vetor2[j]:
            cont2 = cont2 + 1   
    cont_array2.append(cont2)

cont_array1 = []
for i in range(0,len(inter),1):
    cont1 = 0
    for j in range(0, len(vetor1), 1):
        if inter[i]==vetor1[j]:
            cont1 = cont1 + 1   
    cont_array1.append(cont1)

n_elements = np.subtract(cont_array1, cont_array2)

vetor2_1 = []
for i in range(len(n_elements)):
    if n_elements[i]!=0:
        vetor2_1.append(inter[i]*np.ones(n_elements[i]))

vetor2_2 = []
for data1 in vetor1:
    if data1 not in inter:
        vetor2_2.append(data1)

vetor3 = sorted(vetor2_1 + vetor2_2)
print(vetor3) 

The result I am getting is:

[array([2.]), array([3.]), 5]

I imagine the problem is in:

vetor2_1.append(inter[i]*np.ones(n_elements[i]))

Because:

print(vetor2_1)

Gives me:

[array([2.]), array([3.])]

What should I do since I am not receving as answer [2, 3, 5]?

Answer 1

IIUC, you can turn all your algorithm into one line:

a = [1, 2, 2, 3, 3, 5]

b = [1, 2, 3]

c = [a.pop(a.index(i)) for i in b] #Works even with strings.

Output:

[2, 3, 5]

If you need to parametrize something, you can turn it into a function. This will work with sorted(random.sample(vetor1, 3)) , but I didn't use it for replicability.

Answer 2

//generating a random index for array a, to take 3 elements out of it
my_random_int = random.randint(0,len(a)-2)

//popping the element out of the array to put them in b

for x in range(0,2):
    b[x]=a.pop(my_random_int+x)

sources:

https://www.programiz.com/python-programming/methods/list/pop

https://www.edureka.co/blog/generate-random-number-in-python/