I have list lst = [1, 2, 3, 4, 5, 6, 3, 5, 3] and to every iteration, where elem == 3 I want to print strings before that, while elem not is 3 again.
I want to get
2 3:
0 1
1 2
6 3:
3 4
4 5
5 6
8 3:
7 5
But I don't know, how to go to previous string
for i, el in enumerate(lst):
if lst[i] == 3:
print i, el
i -= 1
But it's inly elem-1
Something like this?
lst = [1, 2, 3, 4, 5, 6, 3, 5, 3]
previous = []
for i, el in enumerate(lst):
if lst[i] == 3:
print i, el,":"
for p in previous:
print p[0] , p[1]
previous = []
else:
previous.append((i,el))
You might try implementing with slices as in:
lst = [1, 2, 3, 4, 5, 6, 3, 5, 3]
start_pos = 0
for idx, val in enumerate(lst):
if val == 3:
print idx,val,":"
for p_idx, p_val in enumerate(lst[start_pos:idx]):
print p_idx+start_pos,p_val
start_pos = idx+1
