def stem(self, word, alternate_vowels=False):
        """Return Snowball German stem.

        Parameters
        ----------
        word : str
            The word to stem
        alternate_vowels : bool
            Composes ae as ä, oe as ö, and ue as ü before running the algorithm

        Returns
        -------
        str
            Word stem

        Examples
        --------
        >>> stmr = SnowballGerman()
        >>> stmr.stem('lesen')
        'les'
        >>> stmr.stem('graues')
        'grau'
        >>> stmr.stem('buchstabieren')
        'buchstabi'

        """
        # lowercase, normalize, and compose
        word = normalize('NFC', word.lower())
        word = word.replace('ß', 'ss')

        if len(word) > 2:
            for i in range(2, len(word)):
                if word[i] in self._vowels and word[i - 2] in self._vowels:
                    if word[i - 1] == 'u':
                        word = word[: i - 1] + 'U' + word[i:]
                    elif word[i - 1] == 'y':
                        word = word[: i - 1] + 'Y' + word[i:]

        if alternate_vowels:
            word = word.replace('ae', 'ä')
            word = word.replace('oe', 'ö')
            word = word.replace('que', 'Q')
            word = word.replace('ue', 'ü')
            word = word.replace('Q', 'que')

        r1_start = max(3, self._sb_r1(word))
        r2_start = self._sb_r2(word)

        # Step 1
        niss_flag = False
        if word[-3:] == 'ern':
            if len(word[r1_start:]) >= 3:
                word = word[:-3]
        elif word[-2:] == 'em':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'er':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'en':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
                niss_flag = True
        elif word[-2:] == 'es':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
                niss_flag = True
        elif word[-1:] == 'e':
            if len(word[r1_start:]) >= 1:
                word = word[:-1]
                niss_flag = True
        elif word[-1:] == 's':
            if (
                len(word[r1_start:]) >= 1
                and len(word) >= 2
                and word[-2] in self._s_endings
            ):
                word = word[:-1]

        if niss_flag and word[-4:] == 'niss':
            word = word[:-1]

        # Step 2
        if word[-3:] == 'est':
            if len(word[r1_start:]) >= 3:
                word = word[:-3]
        elif word[-2:] == 'en':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'er':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'st':
            if (
                len(word[r1_start:]) >= 2
                and len(word) >= 6
                and word[-3] in self._st_endings
            ):
                word = word[:-2]

        # Step 3
        if word[-4:] == 'isch':
            if len(word[r2_start:]) >= 4 and word[-5] != 'e':
                word = word[:-4]
        elif word[-4:] in {'lich', 'heit'}:
            if len(word[r2_start:]) >= 4:
                word = word[:-4]
                if word[-2:] in {'er', 'en'} and len(word[r1_start:]) >= 2:
                    word = word[:-2]
        elif word[-4:] == 'keit':
            if len(word[r2_start:]) >= 4:
                word = word[:-4]
                if word[-4:] == 'lich' and len(word[r2_start:]) >= 4:
                    word = word[:-4]
                elif word[-2:] == 'ig' and len(word[r2_start:]) >= 2:
                    word = word[:-2]
        elif word[-3:] in {'end', 'ung'}:
            if len(word[r2_start:]) >= 3:
                word = word[:-3]
                if (
                    word[-2:] == 'ig'
                    and len(word[r2_start:]) >= 2
                    and word[-3] != 'e'
                ):
                    word = word[:-2]
        elif word[-2:] in {'ig', 'ik'}:
            if len(word[r2_start:]) >= 2 and word[-3] != 'e':
                word = word[:-2]

        # Change 'Y' and 'U' back to lowercase if survived stemming
        for i in range(0, len(word)):
            if word[i] == 'Y':
                word = word[:i] + 'y' + word[i + 1 :]
            elif word[i] == 'U':
                word = word[:i] + 'u' + word[i + 1 :]

        # Remove umlauts
        _umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou'))
        word = word.translate(_umlauts)

        return word
def stem(self, word, alternate_vowels=False):
        """Return Snowball German stem.

        Parameters
        ----------
        word : str
            The word to stem
        alternate_vowels : bool
            Composes ae as ä, oe as ö, and ue as ü before running the algorithm

        Returns
        -------
        str
            Word stem

        Examples
        --------
        >>> stmr = SnowballGerman()
        >>> stmr.stem('lesen')
        'les'
        >>> stmr.stem('graues')
        'grau'
        >>> stmr.stem('buchstabieren')
        'buchstabi'

        """
        # lowercase, normalize, and compose
        word = normalize('NFC', word.lower())
        word = word.replace('ß', 'ss')

        if len(word) > 2:
            for i in range(2, len(word)):
                if word[i] in self._vowels and word[i - 2] in self._vowels:
                    if word[i - 1] == 'u':
                        word = word[: i - 1] + 'U' + word[i:]
                    elif word[i - 1] == 'y':
                        word = word[: i - 1] + 'Y' + word[i:]

        if alternate_vowels:
            word = word.replace('ae', 'ä')
            word = word.replace('oe', 'ö')
            word = word.replace('que', 'Q')
            word = word.replace('ue', 'ü')
            word = word.replace('Q', 'que')

        r1_start = max(3, self._sb_r1(word))
        r2_start = self._sb_r2(word)

        # Step 1
        niss_flag = False
        if word[-3:] == 'ern':
            if len(word[r1_start:]) >= 3:
                word = word[:-3]
        elif word[-2:] == 'em':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'er':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'en':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
                niss_flag = True
        elif word[-2:] == 'es':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
                niss_flag = True
        elif word[-1:] == 'e':
            if len(word[r1_start:]) >= 1:
                word = word[:-1]
                niss_flag = True
        elif word[-1:] == 's':
            if (
                len(word[r1_start:]) >= 1
                and len(word) >= 2
                and word[-2] in self._s_endings
            ):
                word = word[:-1]

        if niss_flag and word[-4:] == 'niss':
            word = word[:-1]

        # Step 2
        if word[-3:] == 'est':
            if len(word[r1_start:]) >= 3:
                word = word[:-3]
        elif word[-2:] == 'en':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'er':
            if len(word[r1_start:]) >= 2:
                word = word[:-2]
        elif word[-2:] == 'st':
            if (
                len(word[r1_start:]) >= 2
                and len(word) >= 6
                and word[-3] in self._st_endings
            ):
                word = word[:-2]

        # Step 3
        if word[-4:] == 'isch':
            if len(word[r2_start:]) >= 4 and word[-5] != 'e':
                word = word[:-4]
        elif word[-4:] in {'lich', 'heit'}:
            if len(word[r2_start:]) >= 4:
                word = word[:-4]
                if word[-2:] in {'er', 'en'} and len(word[r1_start:]) >= 2:
                    word = word[:-2]
        elif word[-4:] == 'keit':
            if len(word[r2_start:]) >= 4:
                word = word[:-4]
                if word[-4:] == 'lich' and len(word[r2_start:]) >= 4:
                    word = word[:-4]
                elif word[-2:] == 'ig' and len(word[r2_start:]) >= 2:
                    word = word[:-2]
        elif word[-3:] in {'end', 'ung'}:
            if len(word[r2_start:]) >= 3:
                word = word[:-3]
                if (
                    word[-2:] == 'ig'
                    and len(word[r2_start:]) >= 2
                    and word[-3] != 'e'
                ):
                    word = word[:-2]
        elif word[-2:] in {'ig', 'ik'}:
            if len(word[r2_start:]) >= 2 and word[-3] != 'e':
                word = word[:-2]

        # Change 'Y' and 'U' back to lowercase if survived stemming
        for i in range(0, len(word)):
            if word[i] == 'Y':
                word = word[:i] + 'y' + word[i + 1 :]
            elif word[i] == 'U':
                word = word[:i] + 'u' + word[i + 1 :]

        # Remove umlauts
        _umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou'))
        word = word.translate(_umlauts)

        return word
def stem ( self , word , alternate_vowels = False ) : # lowercase, normalize, and compose word = normalize ( 'NFC' , word . lower ( ) ) word = word . replace ( 'ß', ss') if len ( word ) > 2 : for i in range ( 2 , len ( word ) ) : if word [ i ] in self . _vowels and word [ i - 2 ] in self . _vowels : if word [ i - 1 ] == 'u' : word = word [ : i - 1 ] + 'U' + word [ i : ] elif word [ i - 1 ] == 'y' : word = word [ : i - 1 ] + 'Y' + word [ i : ] if alternate_vowels : word = word . replace ( 'ae' , 'ä') word = word . replace ( 'oe' , 'ö') word = word . replace ( 'que' , 'Q' ) word = word . replace ( 'ue' , 'ü') word = word . replace ( 'Q' , 'que' ) r1_start = max ( 3 , self . _sb_r1 ( word ) ) r2_start = self . _sb_r2 ( word ) # Step 1 niss_flag = False if word [ - 3 : ] == 'ern' : if len ( word [ r1_start : ] ) >= 3 : word = word [ : - 3 ] elif word [ - 2 : ] == 'em' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 2 : ] == 'er' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 2 : ] == 'en' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] niss_flag = True elif word [ - 2 : ] == 'es' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] niss_flag = True elif word [ - 1 : ] == 'e' : if len ( word [ r1_start : ] ) >= 1 : word = word [ : - 1 ] niss_flag = True elif word [ - 1 : ] == 's' : if ( len ( word [ r1_start : ] ) >= 1 and len ( word ) >= 2 and word [ - 2 ] in self . _s_endings ) : word = word [ : - 1 ] if niss_flag and word [ - 4 : ] == 'niss' : word = word [ : - 1 ] # Step 2 if word [ - 3 : ] == 'est' : if len ( word [ r1_start : ] ) >= 3 : word = word [ : - 3 ] elif word [ - 2 : ] == 'en' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 2 : ] == 'er' : if len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 2 : ] == 'st' : if ( len ( word [ r1_start : ] ) >= 2 and len ( word ) >= 6 and word [ - 3 ] in self . _st_endings ) : word = word [ : - 2 ] # Step 3 if word [ - 4 : ] == 'isch' : if len ( word [ r2_start : ] ) >= 4 and word [ - 5 ] != 'e' : word = word [ : - 4 ] elif word [ - 4 : ] in { 'lich' , 'heit' } : if len ( word [ r2_start : ] ) >= 4 : word = word [ : - 4 ] if word [ - 2 : ] in { 'er' , 'en' } and len ( word [ r1_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 4 : ] == 'keit' : if len ( word [ r2_start : ] ) >= 4 : word = word [ : - 4 ] if word [ - 4 : ] == 'lich' and len ( word [ r2_start : ] ) >= 4 : word = word [ : - 4 ] elif word [ - 2 : ] == 'ig' and len ( word [ r2_start : ] ) >= 2 : word = word [ : - 2 ] elif word [ - 3 : ] in { 'end' , 'ung' } : if len ( word [ r2_start : ] ) >= 3 : word = word [ : - 3 ] if ( word [ - 2 : ] == 'ig' and len ( word [ r2_start : ] ) >= 2 and word [ - 3 ] != 'e' ) : word = word [ : - 2 ] elif word [ - 2 : ] in { 'ig' , 'ik' } : if len ( word [ r2_start : ] ) >= 2 and word [ - 3 ] != 'e' : word = word [ : - 2 ] # Change 'Y' and 'U' back to lowercase if survived stemming for i in range ( 0 , len ( word ) ) : if word [ i ] == 'Y' : word = word [ : i ] + 'y' + word [ i + 1 : ] elif word [ i ] == 'U' : word = word [ : i ] + 'u' + word [ i + 1 : ] # Remove umlauts _umlauts = dict ( zip ( ( ord ( _ ) for _ in 'äöü'),  ' a u')) word = word . translate ( _umlauts ) return word
Return Snowball German stem.

        Parameters
        ----------
        word : str
            The word to stem
        alternate_vowels : bool
            Composes ae as ä, oe as ö, and ue as ü before running the algorithm

        Returns
        -------
        str
            Word stem

        Examples
        --------
        >>> stmr = SnowballGerman()
        >>> stmr.stem('lesen')
        'les'
        >>> stmr.stem('graues')
        'grau'
        >>> stmr.stem('buchstabieren')
        'buchstabi'
Return Snowball German stem .