A `find` function¶

Here is an implementation for the find method.

def find(astring, achar):
    """
    Find and return the index of achar in astring.
    Return -1 if achar does not occur in astring.
    """
    ix = 0
    found = False
    while ix < len(astring) and not found:
        if astring[ix] == achar:
            found = True
        else:
            ix = ix + 1
    if found:
        return ix
    else:
        return -1

print(find("Compsci", "p"))
print(find("Compsci", "C"))
print(find("Compsci", "i"))
print(find("Compsci", "x"))

(ch08_run3)

Since we have now combined these two parts with a logical and, it is necessary for them both to be True to continue iterating. If one part fails, the condition fails and the iteration stops.

When the iteration stops, we simply ask a question to find out why and then return the proper value.

A find function¶

A `find` function¶