How to add item from a list to a list

Question

a = [["line1", "arc1", "line2", "line3", "line4", "line5"], ["line6", "arc2", "line7"]]
b = ["Layer1", "Layer2"]

# result need to be:
c = [["Layer1", "line1", "arc1", "line2", "line3", "line4", "line5"],["Layer2", "line6", "arc2", "line7"]]

Answer 1

probably not the best solution but it works:

a = [["line1", "arc1", "line2"], ["line3", "arc2", "line4"]]
b = ["Layer1", "Layer2"]

c = []
d = []
res = []
c.append(b[0])
c.extend(a[0])
d.append(b[1])
d.extend(a[1])
res.append(c)
res.append(d)

print(res)
# output: [['Layer1', 'line1', 'arc1', 'line2'], ['Layer2', 'line3', 'arc2', 'line4']]
# result need to be:
c = [["Layer1", "line1", "arc1", "line2"],["Layer2", "line3", "arc2", "line4"]]
if you really need to have doublequotes around string you can use replace to do this

Answer 2

a[0].insert(0, b[0])
a[1].insert(0, b[1])

Assuming you are using Python...

Answer 3

Yep. Thats what I was talking about using for loop, Eddy Lucas

Answer 4

You can even use a for loop

Answer 5

Thnx Tomas.
Yes it's pyton.
The lists a and b vary in length in runtime

Answer 6

Thnx for helping Thomas
I tried this:
for x in range(len(b)):
a[x].insert(0, b[x])

print(a)

Answer 7

~ swim ~ I'll try when im at work in about 3 weeks
BTW the lists are a random nr of lines and or arcs. But are always a group or groups on a layer or layers