Basic programming question on find() function

[lel7lel7]

I am familiar with the notation
>>>dna = ....
>>>Ecori = "ATGATG"... .
>>>find(dna, Ecori)
>>>find(dna,Eco ri, 2)

My question is how to i find the second undefined base 'n'
ie.
>>>seq = 'ATGATGnATGnATG '
>>>find(seq, 'n')
6
>>>find(seq, 'n', 2)
6 Does not work - Should say 10

[bvdet]

Your argument '2' is the starting index position, not the second occurrence. Example:

>>> import string
>>> string.find('ATGATGnATGnATG', 'n', 2)
6
>>> string.find('ATGATGnATGnATG', 'n', 7)
10
>>>

The string module has been deprecated for a while now. You should use str object methods instead.

>>> 'ATGATGnATGnATG'.find('n', 2)
6
>>> 'ATGATGnATGnATG'.find('n', 7)
10
>>>

[lel7lel7]

Thanks so much - your really helpful :)