CS 112, Lab 8 – Exercise – Functions Due: Monday, March 27 th , 11:59pm Files: Y
ID: 3834171 • Letter: C
Question
CS 112, Lab 8 – Exercise – Functions
Due: Monday, March 27th, 11:59pm
Files:
You should download tester8L.py from Piazza for testing.
Grading is based on the fraction of passing tests. You can run it like this: python3 tester8L.py gmason76_230_L8.py
If you only want to test some functions, you can run it like this: (only testing extract_negatives) python3 tester8L.py gmason76_230_L8.py extract_negatives
As this is an Exercise, you can read any and all materials, ask us questions, talk with other students, and learn however you best learn in order to solve the task. Just create your own solution from those experiences, and turn in your work.
We can define functions to name a block of code, and then feed it inputs and get an output. Functions also allow us to give default values for parameters, which is useful but needs special attention. We will write functions that are more than just side-effect-free input-output factories.
Notes
You cannot import any modules.
Don't call input() or print() anywhere.
We need you to figure out the "signature" (top line) of some functions, so we don't explicitly show you the parameters lists for those functions. Part of the goal is learning how to choose when to use default parameters, and what default values to use.
You're also learning when to modify the original or not; test cases should target this fact.
Turning It In
Add a comment at the top of the file that indicates your name, userID, G#, lab section, a description of your collaboration partners, as well as any other details you feel like sharing. Please also mention what was most helpful for you. Once you are done, run the testing script once more to make sure you didn't break things while adding these comments. If all is well, go ahead and turn in just your one .py file you've been working on, named with our usual convention (see above), over on BlackBoard to the correct lab assignment. Please don't turn in the tester file or any other extra files, as it will just slow us down.
Grading Rubric
Pass shared test cases 4x25 (zero points for hard-coding)
----------------------------------- TOTAL: 100
Tasks
Implement each of the following functions.
def simple_pig_latin(input, sep=" ", end="."): Accept a string input, which might include multiple words separated by a separator sep and perform the following steps:
Find the list of “words” (Note: “words” are just “zero or more characters separated by a symbol”. So, depending on the separator ' ' or 'a..b' could be a “word”.).
Inspect every “word” and apply the following conversions:
if the word starts with a non-letter or contains no characters, do nothing to it
if the word starts with a vowel, add 'way' to the end
if the word starts with a consonant, place the first letter at the end and add 'ay' o Reassemble the words back into one string and return it, making sure a single sep is padded between any two neighboring words and the final string ends with end.
Assume: the input does not have any capital letters o Go ahead and use string methods like .join(), .split() Examples:
simple_pig_latin("i like this") 'iway ikelay histay.'
# default sep(space) and end(dot)
simple_pig_latin("i like this", sep='.') 'i like thisway.'
# separator is dot, so whole thing is a single “word”
simple_pig_latin("i-like-this","-") 'iway-ikelay-histay.'
# sep is '-' and default end(dot)
simple_pig_latin("i.like.this",sep='.',end='!') 'iway.ikelay.histay!'
# sep is '.' and end is '!'
simple_pig_latin(".") '..'
# only word is '.', so do nothing to it and add a '.' to the end
def replace(xs,old,new,limit=None): Given a list xs, replace occurrences of old value with new value. An optional fourth argument limit is an integer states the maximum number of replacements allowed. You should only replace up to the first limit occurrences of old and leave the rest unchanged. When limit==None, there's truly no limit (and we replace all occurrences of old).
Negative or zero limit: no replacement.
Assume: xs is a list; xs could be empty.
Return None, because the replacement happened in-place.
Examples:
>>> xs = [1,2,1,3,1,4,1,5,1]
>>> replace(xs,1,-1) #returns None
>>> xs
[-1, 2, -1, 3, -1, 4, -1, 5, -1] #replace all
o >>> xs = [1,2,1,3,1,4,1,5,1]
>>> replace(xs,1,-1,2)
>>> xs
[-1, 2, -1, 3, 1, 4, 1, 5, 1] #replace only the first 2 occurrences
o >>> xs = [1,2,1,3,1,4,1,5,1]
>>> replace(xs,1,-1,-100)
>>> xs
[1, 2, 1, 3, 1, 4, 1, 5, 1] #replace none
• extract_negatives: The first argument, xs, contains integers. We will be removing any negative integers we find in xs, and appending them to the second argument, new_home. A reference to the list that received negatives must be returned. When no second argument is given, a list of all the extracted negatives should be created and returned.
Figuring out the signature of this function is part of the task. Careful: What default value do you want to use for new_home? What happens when we call the function multiple times in the same coding session? (try it out)
Go ahead and use methods like .insert(), .pop(), .append()
You might need to iterate and update the list at the same time. Hint: if you need to traverse a list from front to back, but you don't always want to go to the next index location, while loops can be very useful – we get to control when (which iteration) to step forward.
Examples:
>>> xs = [1,-22,3,-44,-5,6,7]
>>> extract_negatives(xs)
[-22, -44, -5] #return a list of negatives >>> xs
[1, 3, 6, 7] #remove negatives from xs
o >>> xs = [1,-22,3,-44,-5,6,7]
>>> negatives = [-3, -1]
>>> extract_negatives(xs, negatives)
[-3, -1, -22,-44,-5]
>>> negatives
[-3, -1, -22,-44,-5] #new negatives appended to the list
>>> xs
[1, 3, 6, 7]
Explanation / Answer
Hi there I have written a few tests at the end. You can observe the behaviour and write down what's happening. Something real interesting is happening at extract negatives when we pass reference instead of value. Have a look at that and search the internet a bit. Well most of code is pretty obvious, but still may not be too obvious for beginners, If you have an understanding issue please comment I'd love to reply. Have a great day.
Cheers,
Rj
import re
def simple_pig_latin(inpt, sep=" ", end="."):
words = inpt.split(sep)
out = ""
for word in words:
# First word 'Alpha'
alpha_0 = re.compile(r"^[a-zA-z].*")
# First word 'Vowel'
vowel_0 = re.compile(r"^[aeiouAEIOU].*")
# First word 'Consonant'
vowel_0 = re.compile(r"^[aeiouAEIOU].*")
if (re.match(alpha_0, word[0]) == None):
pass
elif (re.match(vowel_0, word[0]) != None):
word += "way"
elif (re.match(vowel_0, word[0]) == None):
word = word[1:] + word[0] + "ay"
out += word + sep
out = out[:-1] + end
return out
def replace(xs, old, new, limit=None):
if (len(xs) == 0):
return None;
elif (limit == None):
for i in range(len(xs)):
if (xs[i] == old):
xs[i] = new
return xs
elif (limit < 1):
return xs
elif (limit >= 1):
for i in range(limit):
if (xs[i] == old):
xs[i] == new
return xs
else:
return xs
def extract_negatives(xs, new_home = []):
i = 0
while (i < len(xs)):
if (xs[i] < 0):
new_home.append(xs.pop(i))
else:
i += 1
return new_home[:]
# TESTS
# ====
print(simple_pig_latin("i like this"))
print(simple_pig_latin("."))
print(simple_pig_latin("i.like.this",sep='.',end='!'))
print(simple_pig_latin("i-like-this","-"))
print(replace(['anim@l', 'Animal', 'ANIMAL', 'aNIMAL'], 'Animal', '@nimal'))
print(extract_negatives([1,-22,3,-44,-5,6,7]))
print(extract_negatives([1,-22,3,-44,-5,6,7]))