`data_util` Module

Introduction

In this assignment you’ll practice

writing functions and modules,
manipulating strings and data structures,
testing modules with doctest.

Problem Description

You need to manipulate Python data (and you’re not familiar with Python’s standard library).

Solution Description

Create a module named data_util that implements the functions described below.

`doctest`

The specification for each function is given as a docstring – which you should include in your code – and the types of arguments and return values are given using type hints documented in PEP 484 – Type Hints.

Because each function will have a docstring that includes usage examples formatted as Python interactive sessions, you can use doctest to test your code using this command line invocation:

python -m doctest -v data_util.py

If all the tests pass, then you’ll probably (but not defnitely) get a 100 on this homework.

Required Functions

Implement the following functions in your data_util.py file. For convenience you can simply copy the code below.

IMPORTANT: Do not modify the provided docstrings!

def split(text, delim=","):
    """Return a list of fields in text separated by delim.

    Parameters:
    text: str -- the string to split into fields

    Return:
    list[str]

    Usage examples:
    >>> split("foo, bar, baz")
    ['foo', ' bar', ' baz']
    """

def zip(xs, ys):
    """Return [(x0, y0), ..., (xn, yn)] where n is 1 - min(len(xs), len(ys))

    Parameters:
    xs: Sequence -- the "left" list
    ys: Sequence -- the "right list

    Return:
    list[tuple]

    Usage examples:
    >>> zip(['a', 'b', 'c', 'd'], [1,2,3])
    [('a', 1), ('b', 2), ('c', 3)]
    """

def zip_with_indexes(xs):
    """Return [(0, x0), ..., (n, xn)] where n is 1 - len(xs)

    Parameters:
    xs: Sequence -- a sequence

    Return:
    list[tuple]

    Usage examples:
    >>> zip_with_indexes(['a', 'b', 'c', 'd'])
    [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')]
    """

def lookup_key(v, d):
    """Return a key in dict d which maps to v, or None if v isn't present

    Parameters:
    v: Any -- a value which may be in dictionary d
    d, : dict -- a dictionary which may contain the value v

    Return:
    Any

    Usage examples:
    >>> lookup_key(1, {'a': 1, 1: 'b', 'c': 2})
    'a'
    """

def lookup_keys(v, d):
    """Return list of keys in dict d which map to value

    Parameters:
    v: Any -- a value which may be in dictionary d
    d, : dict -- a dictionary which may contain the value v

    Return:
    list[Any]

    Usage examples:
    >>> lookup_keys(1, {'a': 1, 1: 'b', 'c': 2, 'd': 1})
    ['a', 'd']
    """

Sample Solution

data_util.py

data_util Module