Python For loop not incrementing

Question

clean_offset = len(malware)

tuple_clean = []
tuple_malware = []

for i in malware:
    tuple_malware.append([malware.index(i), 0])
    print(malware.index(i))
    print(tuple_malware)
for j in clean:
    tuple_clean.append([(clean_offset + clean.index(j)), 1])
    print(clean.index(j))
    print(tuple_clean)
    import pdb; pdb.set_trace()

training_data_size_mal = 0.8 * len(malware)
training_data_size_clean = 0.8 * len(clean)

i increments as normal and produces correct output however j remains at 0 for three loops and then jumps to 3. I don’t understand this.

Asked By: qz_99

||

Source

Answer 1

for a in something

a is what is contained in something, not the index

for example:

for n in [1, 10, 9, 3]:
    print(n)

gives

Answered By: Pedru

Answer 2

You either want

for i in range(len(malware))

or

for i, element in enumerate(malware)

at which point the i is the count and the element in the malware.index(i)

The last one is considered best practice when needing both the index and the element at that index in the loop.

Answered By: Victor Sonck

Answer 3

There is a logical error on clean.index(j).
Array.index will return the first matched index in that array.
So if there are some equal variables there will be some error

You can inspect with below code.

malware = [1,2,3,4,5,6,7,8,8,8,8,8,2]
clean = [1,2,3,4,4,4,4,4,4,2,4,4,4,4]

clean_offset = len(malware)

tuple_clean = []
tuple_malware = []

for i in malware:
    tuple_malware.append([malware.index(i), 0])
    print(malware.index(i))
    print(tuple_malware)
for j in clean:
    tuple_clean.append([(clean_offset + clean.index(j)), 1])
    print(clean.index(j))
    print(tuple_clean)

training_data_size_mal = 0.8 * len(malware)
training_data_size_clean = 0.8 * len(clean)

Answered By: Barkın BOZ

Answer 4

op has already figured the question, but in case anyone is wondering or needs a TL;DR of Barkin’s comment, its just a small correction,

replace

for i in malware

for j in clean

with

for i in range(len(malware))

for j in range(len(clean))

and at the end remove the .index() function, and place i and j.

Answered By: 9dubs

Python For loop not incrementing

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