newb: comapring two strings

[manstey]

Hi,

Is there a clever way to see if two strings of the same length vary by
only one character, and what the character is in both strings.

E.g. str1=yaqtil str2=yaqtel

they differ at str1[4] and the difference is ('i','e')

But if there was str1=yiqtol and str2=yaqtel, I am not interested.

can anyone suggest a simple way to do this?

My next problem is, I have a list of 300,000+ words and I want to find
every pair of such strings. I thought I would first sort on length of
string, but how do I iterate through the following:

str1
str2
str3
str4
str5

so that I compare str1 & str2, str1 & str3, str 1 & str4, str1 & str5,
str2 & str3, str3 & str4, str3 & str5, str4 & str5.

Thanks in advance,
Matthew