# Help me in solving PYSTRARR1 problem

### My issue

explain

Learning course: Strings using Python
Problem Link: CodeChef: Practical coding for everyone

``````while i < (len(u)-1):
if u[i] == 't' and u[i+1] == 'h':
print('Yes')
break
i = i + 1
if i == (len(u) - 1):
print('no')
``````

Explanation:

I am assuming you are familiar with basics of strings and loops.

Basically we are iterating through the string to check if any character in string is ‘`t`’ AND its immediately followed by ‘`h`’. We are using a while loop for this: if integer `'i'` is less than length of string ‘`u`’ -1 we check if `u[i]` is ‘`t`’ AND `u[i+1]` is ‘`h`’ or not. If it is we print “Yes” and break out of loop, else we just increase ‘i’ and check for this new ‘i’.

Note we are looping from 0 to `len(u)-2` (not `len(u)-1`) as we are checking `i` and `i+1` (incase of `len(u)-1`, it will give segmentation fault, as `u[i+1] = u[len(u)]` doesn’t exist.)

Anyway, if we don’t find any `'th'` the loop will end with value of `i = len(u)-1`. So if we have` i == len(u)-1`, we print “No”

Let me know if anything confuses you.