<filename>cardinal_pythonlib/stringfunc.py
#!/usr/bin/env python
# cardinal_pythonlib/sqlalchemy/subproc.py

"""
===============================================================================

    Original code copyright (C) 2009-2020 <NAME> (<EMAIL>).

    This file is part of cardinal_pythonlib.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.

===============================================================================
"""

import re
from typing import Any, Dict, Iterable, List
import unicodedata


# =============================================================================
# Finding
# =============================================================================

def find_nth(s: str, x: str, n: int = 0, overlap: bool = False) -> int:
    """
    Finds the position of *n*\ th occurrence of ``x`` in ``s``, or ``-1`` if
    there isn't one.

    - The ``n`` parameter is zero-based (i.e. 0 for the first, 1 for the
      second...).
    - If ``overlap`` is true, allows fragments to overlap. If not, they must be
      distinct.
      
    As per
    https://stackoverflow.com/questions/1883980/find-the-nth-occurrence-of-substring-in-a-string 
    """  # noqa
    length_of_fragment = 1 if overlap else len(x)
    i = -length_of_fragment
    for _ in range(n + 1):
        i = s.find(x, i + length_of_fragment)
        if i < 0:
            break
    return i


# =============================================================================
# Splitting
# =============================================================================

def split_string(x: str, n: int) -> List[str]:
    """
    Split string into chunks of length n
    """
    # https://stackoverflow.com/questions/9475241/split-string-every-nth-character  # noqa
    return [x[i:i+n] for i in range(0, len(x), n)]


# =============================================================================
# Replacement
# =============================================================================

def multiple_replace(text: str, rep: Dict[str, str]) -> str:
    """
    Returns a version of ``text`` in which the keys of ``rep`` (a dict) have
    been replaced by their values.

    As per
    http://stackoverflow.com/questions/6116978/python-replace-multiple-strings.
    """
    rep = dict((re.escape(k), v) for k, v in rep.items())
    pattern = re.compile("|".join(rep.keys()))
    return pattern.sub(lambda m: rep[re.escape(m.group(0))], text)


def replace_in_list(stringlist: Iterable[str],
                    replacedict: Dict[str, str]) -> List[str]:
    """
    Returns a list produced by applying :func:`multiple_replace` to every
    string in ``stringlist``.

    Args:
        stringlist: list of source strings
        replacedict: dictionary mapping "original" to "replacement" strings

    Returns:
        list of final strings

    """
    newlist = []
    for fromstring in stringlist:
        newlist.append(multiple_replace(fromstring, replacedict))
    return newlist


# =============================================================================
# Mangling to ASCII
# =============================================================================

def mangle_unicode_to_ascii(s: Any) -> str:
    """
    Mangle unicode to ASCII, losing accents etc. in the process.
    """
    # http://stackoverflow.com/questions/1207457
    if s is None:
        return ""
    if not isinstance(s, str):
        s = str(s)
    return (
        unicodedata.normalize('NFKD', s)
                   .encode('ascii', 'ignore')  # gets rid of accents
                   .decode('ascii')  # back to a string
    )


# =============================================================================
# Making strings and string lists
# =============================================================================

def strnum(prefix: str, num: int, suffix: str = "") -> str:
    """
    Makes a string of the format ``<prefix><number><suffix>``.
    """
    return f"{prefix}{num}{suffix}"


def strnumlist(prefix: str, numbers: List[int], suffix: str = "") -> List[str]:
    """
    Makes a string of the format ``<prefix><number><suffix>`` for every number
    in ``numbers``, and returns them as a list.
    """
    return [f"{prefix}{num}{suffix}" for num in numbers]


def strseq(prefix: str, first: int, last: int, suffix: str = "") -> List[str]:
    """
    Makes a string of the format ``<prefix><number><suffix>`` for every number
    from ``first`` to ``last`` inclusive, and returns them as a list.
    """
    return [strnum(prefix, n, suffix) for n in range(first, last + 1)]

<filename>cardinal_pythonlib/stringfunc.py
#!/usr/bin/env python
# cardinal_pythonlib/sqlalchemy/subproc.py

"""
===============================================================================

    Original code copyright (C) 2009-2020 <NAME> (<EMAIL>).

    This file is part of cardinal_pythonlib.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.

===============================================================================
"""

import re
from typing import Any, Dict, Iterable, List
import unicodedata


# =============================================================================
# Finding
# =============================================================================

def find_nth(s: str, x: str, n: int = 0, overlap: bool = False) -> int:
    """
    Finds the position of *n*\ th occurrence of ``x`` in ``s``, or ``-1`` if
    there isn't one.

    - The ``n`` parameter is zero-based (i.e. 0 for the first, 1 for the
      second...).
    - If ``overlap`` is true, allows fragments to overlap. If not, they must be
      distinct.
      
    As per
    https://stackoverflow.com/questions/1883980/find-the-nth-occurrence-of-substring-in-a-string 
    """  # noqa
    length_of_fragment = 1 if overlap else len(x)
    i = -length_of_fragment
    for _ in range(n + 1):
        i = s.find(x, i + length_of_fragment)
        if i < 0:
            break
    return i


# =============================================================================
# Splitting
# =============================================================================

def split_string(x: str, n: int) -> List[str]:
    """
    Split string into chunks of length n
    """
    # https://stackoverflow.com/questions/9475241/split-string-every-nth-character  # noqa
    return [x[i:i+n] for i in range(0, len(x), n)]


# =============================================================================
# Replacement
# =============================================================================

def multiple_replace(text: str, rep: Dict[str, str]) -> str:
    """
    Returns a version of ``text`` in which the keys of ``rep`` (a dict) have
    been replaced by their values.

    As per
    http://stackoverflow.com/questions/6116978/python-replace-multiple-strings.
    """
    rep = dict((re.escape(k), v) for k, v in rep.items())
    pattern = re.compile("|".join(rep.keys()))
    return pattern.sub(lambda m: rep[re.escape(m.group(0))], text)


def replace_in_list(stringlist: Iterable[str],
                    replacedict: Dict[str, str]) -> List[str]:
    """
    Returns a list produced by applying :func:`multiple_replace` to every
    string in ``stringlist``.

    Args:
        stringlist: list of source strings
        replacedict: dictionary mapping "original" to "replacement" strings

    Returns:
        list of final strings

    """
    newlist = []
    for fromstring in stringlist:
        newlist.append(multiple_replace(fromstring, replacedict))
    return newlist


# =============================================================================
# Mangling to ASCII
# =============================================================================

def mangle_unicode_to_ascii(s: Any) -> str:
    """
    Mangle unicode to ASCII, losing accents etc. in the process.
    """
    # http://stackoverflow.com/questions/1207457
    if s is None:
        return ""
    if not isinstance(s, str):
        s = str(s)
    return (
        unicodedata.normalize('NFKD', s)
                   .encode('ascii', 'ignore')  # gets rid of accents
                   .decode('ascii')  # back to a string
    )


# =============================================================================
# Making strings and string lists
# =============================================================================

def strnum(prefix: str, num: int, suffix: str = "") -> str:
    """
    Makes a string of the format ``<prefix><number><suffix>``.
    """
    return f"{prefix}{num}{suffix}"


def strnumlist(prefix: str, numbers: List[int], suffix: str = "") -> List[str]:
    """
    Makes a string of the format ``<prefix><number><suffix>`` for every number
    in ``numbers``, and returns them as a list.
    """
    return [f"{prefix}{num}{suffix}" for num in numbers]


def strseq(prefix: str, first: int, last: int, suffix: str = "") -> List[str]:
    """
    Makes a string of the format ``<prefix><number><suffix>`` for every number
    from ``first`` to ``last`` inclusive, and returns them as a list.
    """
    return [strnum(prefix, n, suffix) for n in range(first, last + 1)]

#!/usr/bin/env python # cardinal_pythonlib/sqlalchemy/subproc.py ===============================================================================      Original code copyright (C) 2009-2020 <NAME> (<EMAIL>).      This file is part of cardinal_pythonlib.      Licensed under the Apache License, Version 2.0 (the "License");     you may not use this file except in compliance with the License.     You may obtain a copy of the License at          http://www.apache.org/licenses/LICENSE-2.0      Unless required by applicable law or agreed to in writing, software     distributed under the License is distributed on an "AS IS" BASIS,     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.     See the License for the specific language governing permissions and     limitations under the License.  =============================================================================== # ============================================================================= # Finding # ============================================================================= Finds the position of *n*\ th occurrence of ``x`` in ``s``, or ``-1`` if     there isn't one.      - The ``n`` parameter is zero-based (i.e. 0 for the first, 1 for the       second...).     - If ``overlap`` is true, allows fragments to overlap. If not, they must be       distinct.            As per     https://stackoverflow.com/questions/1883980/find-the-nth-occurrence-of-substring-in-a-string # noqa # ============================================================================= # Splitting # ============================================================================= Split string into chunks of length n # https://stackoverflow.com/questions/9475241/split-string-every-nth-character  # noqa # ============================================================================= # Replacement # ============================================================================= Returns a version of ``text`` in which the keys of ``rep`` (a dict) have     been replaced by their values.      As per     http://stackoverflow.com/questions/6116978/python-replace-multiple-strings. Returns a list produced by applying :func:`multiple_replace` to every     string in ``stringlist``.      Args:         stringlist: list of source strings         replacedict: dictionary mapping "original" to "replacement" strings      Returns:         list of final strings # ============================================================================= # Mangling to ASCII # ============================================================================= Mangle unicode to ASCII, losing accents etc. in the process. # http://stackoverflow.com/questions/1207457 # gets rid of accents # back to a string # ============================================================================= # Making strings and string lists # ============================================================================= Makes a string of the format ``<prefix><number><suffix>``. Makes a string of the format ``<prefix><number><suffix>`` for every number     in ``numbers``, and returns them as a list. Makes a string of the format ``<prefix><number><suffix>`` for every number     from ``first`` to ``last`` inclusive, and returns them as a list.