# -*- coding: utf-8 -*-
#!/usr/bin/env python


def locations(subseq, seq):
    locs = []
    i = 0
    for elem in seq:
        if elem == subseq: locs.append(i)
        i += 1
    return locs

def ngrams(s,n):
    """
            >>> ngrams('abcddlagk', 3)
            ['abc', 'bcd', 'cdd', 'ddl', 'dla', 'lag', 'agk']
            >>> ngrams('abcde', 2)
            [('ab'), ('bc'), ('cd'), ('de')]
    """
    return  [tuple(s[i:i+n]) for i in range(len(s)-n+1)]


def bigrams(s): return ngrams(s,2)


def offsets(seq):
    """
    return the intervals between the elements in list of ints.
    
    >>> offsets([1, 3, 5])
    [2, 2]
    """
    offs = []


        
    

def _test():
    import doctest
    import chardist
    myoptionflags = doctest.ELLIPSIS|doctest.NORMALIZE_WHITESPACE
    doctest.testmod(optionflags=myoptionflags)

if __name__ == "__main__":
    _test()