how to reset pointer of list in for loop after a condition becomes true in python? -

for r in right:     if stack.endswith(r):         stack=stack.replace(r,left[right.index(r)]) 

when if part gets true want r point starting index of right.

suppose r pointing 3rd element of right when if gets true , updates stack, for loop continues 3rd element of right. want start for loop first element of right whenever stack updated.

how it?

one cool way use explicit iterator

iterator = iter(right) try:     while true:         r = next(iterator)         if stack.endswith(r):             stack = stack.replace(r, left[right.index(r)])             iterator = iter(right)  except stopiteration:     pass         

which in case looks pretty horrible there no "has_next" method iterators, , way know when stop catch exception; , loop not work here because stores reference iterator

but idiomatic python in exact case use else clause of for loop break out while:

# loop forever while true:     r in right:         if stack.endswith(r):             stack = stack.replace(r, left[right.index(r)])              # break out of for-loop rerunning while             break     # else run when r in right consumed     else:         # break not in loop; breaks while         break