CODEWITHSUNDEEP
pythonlist
Chris V
Chris V

Reputation: 3

2 lists of data with second list describing first, splitting the first in new lists

All values in list B are either 1.0 or 2. I'm trying to go through listA (coded as "Time1) and depending on each corresponding value in listB (Coded as Channel1) sort each term into a new list. aka:

A = [2.3, 4.3, 3.1] 
B = [1.0, 2.0, 1.0]

becomes

P = [2.3, 3.1] 
Q = [4.3]

My current code for this is:

 a = 0

 for a in Time1:

     if Channel1[a] == 1:

         HistDetec1.append(Time1[a])

     if Channel1[a] == 2:

         HistDetec1.append(Time1[a])

     a = a + 1

But this doesn't work as it think that "a" is a float 

list indices must be integers, not float

Thanks for your time.

Upvotes: 0

Views: 31

Answers (3)

alpert
alpert

Reputation: 4655

There are a few mistakes.

1 - First you are looping through the elements of A instead of indexes and try to use that elements as indexes at other list.

2 - You are appending in either case to the same list HistDetec1

3 - You try to increment index which for already do that

4 - You check equality of int values against float values

Try something like that:

for index in range(len(Time1)):
    if Channel1[index] == 1.0:
         HistDetec1.append(Time1[index])
    elif Channel1[index] == 2.0:
         HistDetec2.append(Time1[index])

Upvotes: 0

casraf
casraf

Reputation: 21694

You can just use an integer there...

B = [1, 2, 1]

Or convert to integer before checking:

if Channel1[int(a)] == 1:

Upvotes: 0

AKS
AKS

Reputation: 19851

You could use enumerate and list comprehension:

>>> A = [2.3, 4.3, 3.1]
>>> B = [1.0, 2.0, 1.0]
>>> P = [t for i, t in enumerate(A) if B[i] == 1.0]
>>> P
[2.3, 3.1]
>>> Q = [t for i, t in enumerate(A) if B[i] == 2.0]
>>> Q
[4.3]

Or, using zip:

>>> P = [a for a, b in zip(A, B) if b == 1.0]
>>> P
[2.3, 3.1]
>>> Q = [a for a, b in zip(A, B) if b == 2.0]
>>> Q
[4.3]

Upvotes: 1

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