def dist_abs(self, src, tar, max_offset=5, max_distance=0):
        """Return the "common" Sift4 distance between two terms.

        Parameters
        ----------
        src : str
            Source string for comparison
        tar : str
            Target string for comparison
        max_offset : int
            The number of characters to search for matching letters
        max_distance : int
            The distance at which to stop and exit

        Returns
        -------
        int
            The Sift4 distance according to the common formula

        Examples
        --------
        >>> cmp = Sift4()
        >>> cmp.dist_abs('cat', 'hat')
        1
        >>> cmp.dist_abs('Niall', 'Neil')
        2
        >>> cmp.dist_abs('Colin', 'Cuilen')
        3
        >>> cmp.dist_abs('ATCG', 'TAGC')
        2

        """
        if not src:
            return len(tar)

        if not tar:
            return len(src)

        src_len = len(src)
        tar_len = len(tar)

        src_cur = 0
        tar_cur = 0
        lcss = 0
        local_cs = 0
        trans = 0
        offset_arr = []

        while (src_cur < src_len) and (tar_cur < tar_len):
            if src[src_cur] == tar[tar_cur]:
                local_cs += 1
                is_trans = False
                i = 0
                while i < len(offset_arr):
                    ofs = offset_arr[i]
                    if src_cur <= ofs['src_cur'] or tar_cur <= ofs['tar_cur']:
                        is_trans = abs(tar_cur - src_cur) >= abs(
                            ofs['tar_cur'] - ofs['src_cur']
                        )
                        if is_trans:
                            trans += 1
                        elif not ofs['trans']:
                            ofs['trans'] = True
                            trans += 1
                        break
                    elif src_cur > ofs['tar_cur'] and tar_cur > ofs['src_cur']:
                        del offset_arr[i]
                    else:
                        i += 1

                offset_arr.append(
                    {'src_cur': src_cur, 'tar_cur': tar_cur, 'trans': is_trans}
                )
            else:
                lcss += local_cs
                local_cs = 0
                if src_cur != tar_cur:
                    src_cur = tar_cur = min(src_cur, tar_cur)
                for i in range(max_offset):
                    if not (
                        (src_cur + i < src_len) or (tar_cur + i < tar_len)
                    ):
                        break
                    if (src_cur + i < src_len) and (
                        src[src_cur + i] == tar[tar_cur]
                    ):
                        src_cur += i - 1
                        tar_cur -= 1
                        break
                    if (tar_cur + i < tar_len) and (
                        src[src_cur] == tar[tar_cur + i]
                    ):
                        src_cur -= 1
                        tar_cur += i - 1
                        break

            src_cur += 1
            tar_cur += 1

            if max_distance:
                temporary_distance = max(src_cur, tar_cur) - lcss + trans
                if temporary_distance >= max_distance:
                    return round(temporary_distance)

            if (src_cur >= src_len) or (tar_cur >= tar_len):
                lcss += local_cs
                local_cs = 0
                src_cur = tar_cur = min(src_cur, tar_cur)

        lcss += local_cs
        return round(max(src_len, tar_len) - lcss + trans)
def dist_abs(self, src, tar, max_offset=5, max_distance=0):
        """Return the "common" Sift4 distance between two terms.

        Parameters
        ----------
        src : str
            Source string for comparison
        tar : str
            Target string for comparison
        max_offset : int
            The number of characters to search for matching letters
        max_distance : int
            The distance at which to stop and exit

        Returns
        -------
        int
            The Sift4 distance according to the common formula

        Examples
        --------
        >>> cmp = Sift4()
        >>> cmp.dist_abs('cat', 'hat')
        1
        >>> cmp.dist_abs('Niall', 'Neil')
        2
        >>> cmp.dist_abs('Colin', 'Cuilen')
        3
        >>> cmp.dist_abs('ATCG', 'TAGC')
        2

        """
        if not src:
            return len(tar)

        if not tar:
            return len(src)

        src_len = len(src)
        tar_len = len(tar)

        src_cur = 0
        tar_cur = 0
        lcss = 0
        local_cs = 0
        trans = 0
        offset_arr = []

        while (src_cur < src_len) and (tar_cur < tar_len):
            if src[src_cur] == tar[tar_cur]:
                local_cs += 1
                is_trans = False
                i = 0
                while i < len(offset_arr):
                    ofs = offset_arr[i]
                    if src_cur <= ofs['src_cur'] or tar_cur <= ofs['tar_cur']:
                        is_trans = abs(tar_cur - src_cur) >= abs(
                            ofs['tar_cur'] - ofs['src_cur']
                        )
                        if is_trans:
                            trans += 1
                        elif not ofs['trans']:
                            ofs['trans'] = True
                            trans += 1
                        break
                    elif src_cur > ofs['tar_cur'] and tar_cur > ofs['src_cur']:
                        del offset_arr[i]
                    else:
                        i += 1

                offset_arr.append(
                    {'src_cur': src_cur, 'tar_cur': tar_cur, 'trans': is_trans}
                )
            else:
                lcss += local_cs
                local_cs = 0
                if src_cur != tar_cur:
                    src_cur = tar_cur = min(src_cur, tar_cur)
                for i in range(max_offset):
                    if not (
                        (src_cur + i < src_len) or (tar_cur + i < tar_len)
                    ):
                        break
                    if (src_cur + i < src_len) and (
                        src[src_cur + i] == tar[tar_cur]
                    ):
                        src_cur += i - 1
                        tar_cur -= 1
                        break
                    if (tar_cur + i < tar_len) and (
                        src[src_cur] == tar[tar_cur + i]
                    ):
                        src_cur -= 1
                        tar_cur += i - 1
                        break

            src_cur += 1
            tar_cur += 1

            if max_distance:
                temporary_distance = max(src_cur, tar_cur) - lcss + trans
                if temporary_distance >= max_distance:
                    return round(temporary_distance)

            if (src_cur >= src_len) or (tar_cur >= tar_len):
                lcss += local_cs
                local_cs = 0
                src_cur = tar_cur = min(src_cur, tar_cur)

        lcss += local_cs
        return round(max(src_len, tar_len) - lcss + trans)
def dist_abs ( self , src , tar , max_offset = 5 , max_distance = 0 ) : if not src : return len ( tar ) if not tar : return len ( src ) src_len = len ( src ) tar_len = len ( tar ) src_cur = 0 tar_cur = 0 lcss = 0 local_cs = 0 trans = 0 offset_arr = [ ] while ( src_cur < src_len ) and ( tar_cur < tar_len ) : if src [ src_cur ] == tar [ tar_cur ] : local_cs += 1 is_trans = False i = 0 while i < len ( offset_arr ) : ofs = offset_arr [ i ] if src_cur <= ofs [ 'src_cur' ] or tar_cur <= ofs [ 'tar_cur' ] : is_trans = abs ( tar_cur - src_cur ) >= abs ( ofs [ 'tar_cur' ] - ofs [ 'src_cur' ] ) if is_trans : trans += 1 elif not ofs [ 'trans' ] : ofs [ 'trans' ] = True trans += 1 break elif src_cur > ofs [ 'tar_cur' ] and tar_cur > ofs [ 'src_cur' ] : del offset_arr [ i ] else : i += 1 offset_arr . append ( { 'src_cur' : src_cur , 'tar_cur' : tar_cur , 'trans' : is_trans } ) else : lcss += local_cs local_cs = 0 if src_cur != tar_cur : src_cur = tar_cur = min ( src_cur , tar_cur ) for i in range ( max_offset ) : if not ( ( src_cur + i < src_len ) or ( tar_cur + i < tar_len ) ) : break if ( src_cur + i < src_len ) and ( src [ src_cur + i ] == tar [ tar_cur ] ) : src_cur += i - 1 tar_cur -= 1 break if ( tar_cur + i < tar_len ) and ( src [ src_cur ] == tar [ tar_cur + i ] ) : src_cur -= 1 tar_cur += i - 1 break src_cur += 1 tar_cur += 1 if max_distance : temporary_distance = max ( src_cur , tar_cur ) - lcss + trans if temporary_distance >= max_distance : return round ( temporary_distance ) if ( src_cur >= src_len ) or ( tar_cur >= tar_len ) : lcss += local_cs local_cs = 0 src_cur = tar_cur = min ( src_cur , tar_cur ) lcss += local_cs return round ( max ( src_len , tar_len ) - lcss + trans )
Return the "common" Sift4 distance between two terms.

        Parameters
        ----------
        src : str
            Source string for comparison
        tar : str
            Target string for comparison
        max_offset : int
            The number of characters to search for matching letters
        max_distance : int
            The distance at which to stop and exit

        Returns
        -------
        int
            The Sift4 distance according to the common formula

        Examples
        --------
        >>> cmp = Sift4()
        >>> cmp.dist_abs('cat', 'hat')
        1
        >>> cmp.dist_abs('Niall', 'Neil')
        2
        >>> cmp.dist_abs('Colin', 'Cuilen')
        3
        >>> cmp.dist_abs('ATCG', 'TAGC')
        2
Return the common Sift4 distance between two terms .