在Python清单中循环，每个循环使用多个项目

Question

So I'm writing a script for a program called Abaqus.... and I have a list of numbers, and I need to loop through the numbers in the following manner

listOfSteps = [1, 4, 7, 10, 17, 22, 28, 29, 30, 43, 47, 50]
fileNameCreate = 0 

for i in listOfSteps:

    session.viewports['Viewport: 1'].odbDisplay.setFrame(step=i, frame=-1)
    session.viewports['Viewport: 2'].odbDisplay.setFrame(step=i, frame=-1)
    session.viewports['Viewport: 3'].odbDisplay.setFrame(step=i, frame=-1)
    session.printOptions.setValues(reduceColors=False)
    session.printToFile(fileName='C:/Image'+str(fileNameCreate+1), format=PNG, 
        canvasObjects=(session.viewports['Viewport: 3'], 
        session.viewports['Viewport: 2'], session.viewports['Viewport: 1']))

So I need the first step to use 1, 2nd step to use 4, 3rd step to use 7
Then do the code to save the file

Then start the loop again at 10

Any help would be great.

Answer 1

Assuming I've understood your question correctly, you could use an iterator :

listOfSteps = [1, 4, 7, 10, 17, 22, 28, 29, 30, 43, 47, 50]
fileNameCreate = 0 

it = iter(listOfSteps)

for a in it:
    b = next(it)
    c = next(it)

    session.viewports['Viewport: 1'].odbDisplay.setFrame(step=a, frame=-1)
    session.viewports['Viewport: 2'].odbDisplay.setFrame(step=b, frame=-1)
    session.viewports['Viewport: 3'].odbDisplay.setFrame(step=c, frame=-1)

    # ...

And, if you don't mind a little bit of magic:

for a, b, c in zip(*[iter(listOfSteps)]*3):
    # ...

The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n) . ~ Zip Docs

Answer 2

Maybe try to add a counter variable to your code

listOfSteps = [1, 4, 7, 10, 17, 22, 28, 29, 30, 43, 47, 50]
fileNameCreate = 0 
cnt = 0

for i in listOfSteps:
   cnt =+ 1
   if cnt % 3 == 0:
       # here do your write magic