GHpython-extract the list number

Replies to This Discussion

Permalink Reply by vhoang on July 18, 2017 at 2:26am

You can simply use the Member Index component.

If you still want to write GHPython script then maybe you can loop through the list with enumerate() in order to retrieve all the indexes of True values, then append them to a new list. See attached.

Attachments:

• truefalsetrue.gh, 7 KB

Permalink Reply by Tomo Nishimura on July 18, 2017 at 6:32pm

Hi vhoang

I am surprised that there is a simple GH component.
Your code in python is also helpful.

Thank you!!

--

Tomo

Permalink Reply by Chris Hanley on July 18, 2017 at 11:49am

as mentioned, enumerate is probably what you are looking for. From a strictly pythonic approach, it would be some variation of this:

index = [] #list to hold the index, named component output

value = [] #list to hold the value, named component output

enumeratedList = list(enumerate(x)) #example to show results of enumerate

for i,j in enumerate(x): #i is first value, j, is second value

    if j == y: #set input hint type to string and connect boolean toggle

        index.append(i) #append i, (first value) to index list

        value.append(j) #append j, (second value) to value list

Permalink Reply by Tomo Nishimura on July 18, 2017 at 6:45pm

Thank　you!

I thought using the "index" method provided by the list type to get the index of the element. But, only the first index could be extracted.

 "enumerate" is useful.

Permalink Reply by Andrew Heumann on July 19, 2017 at 6:16am

just to add one more python option to the above:

a = [v for v in range(len(x)) if x[v]]

will get it done in a single line. it's not the most readable thing so an explicit loop might be better depending on your purposes, but I am quite fond of the elegance of these list comprehension statements in python. 

Permalink Reply by Chris Hanley on July 19, 2017 at 12:35pm

That is certainly very elegant!  Thanks!.  I need to brush up on my list comprehension.