Python for loop question

Question

I was wondering how to achieve the following in python:

for( int i = 0; cond...; i++)   if cond...     i++; //to skip an run-through 

I tried this with no luck.

for i in range(whatever):   if cond... :     i += 1 

Answer 1

Python's for loops are different. i gets reassigned to the next value every time through the loop.

The following will do what you want, because it is taking the literal version of what C++ is doing:

i = 0 while i < some_value:     if cond...:         i+=1     ...code...     i+=1 

Here's why:

in C++, the following code segments are equivalent:

for(..a..; ..b..; ..c..) {     ...code... } 

and

..a.. while(..b..) {      ..code..      ..c.. } 

whereas the python for loop looks something like:

for x in ..a..:     ..code.. 

turns into

my_iter = iter(..a..) while (my_iter is not empty):     x = my_iter.next()     ..code.. 

Answer 2

There is a continue keyword which skips the current iteration and advances to the next one (and a break keyword which skips all loop iterations and exits the loop):

for i in range(10):     if i % 2 == 0:       # skip even numbers       continue      print i