Python Check In

[philipc2]

Python Check In

UXarray, which is the package you will be contributing to this summer, is written in pure Python. Durring the first week, we will meet to check in on how comfortable you feel working with Python.

You are free to use the internet (including generative AI tools), but try to answer them without explicitly copying the answer and code.

Tools & Environments

1. What operating systems have you worked with before (Windows, Mac, Linux)?
2. Do you have a preferred code editor (i.e. VsCode, PyCharm, etc.)?

Python Style & Syntax

Question 1: Builtins & None Checks

Fill out the following code snippets.

foo = [1, 2, None, 3]
bar = None

# Check whether bar is equal to None (True if it is, False if it isn't)
is_bar_none = ... 

# Find how many times None occurs in the list "foo"
n_none = ...

# create a dictionary of counts for each unique element in the list "foo"
counts = ... 

Question 2: Classes & Attributes

class MyClass:
    foo = "bar"

    def foo():
        return "bar"

MyClass.fooprint = print

1. What does MyClass.foo return? Is it what you expected? Why do you think this is the case?
2. What does MyClass.foo() return?
3. What does MyClass.fooprint = print do? Try calling MyClass.fooprint()

Question 3: CPython & Unexpected Behavior

a = 1
b = 1
print(id(a), id(b)

c = 2024
d = 2024
print(id(c), id(d))

1. What is the id() function doing above?
2. What values did you get for a, b, c, and d.
3. Try the same exercise for values of 255, 256, and 256, -5, and -6
4. Can you explain the behavior you are observing? (You may find this CPython file usefull)

Question 4

Do you have any specific questions for me regarding Python?

[rytam2]

Tools & Environments

1. Operating systems worked with before: Mostly Linux, barely Windows.
2. Preferred code editor: MobaxTerm; some VsCode

[rytam2]

Question 1: Builtins & None Checks

Fill out the following code snippets.

foo = [1, 2, None, 3]
bar = None

# Check whether bar is equal to None (True if it is, False if it isn't)
if bar == None:
  is_bar_none = True
else: 
  is_bar_none = False

# Find how many times None occurs in the list "foo"
n_none = foo.count(None)

# create a dictionary of counts for each unique element in the list "foo"
#### Count with numpy 
fooo = np.array(foo, dtype=float)
keys, values = np.unique(fooo, return_counts=True)
count = dict(zip(keys, values ))

#### Count with Counter package 
##### Ref: https://stackoverflow.com/questions/12282232/how-do-i-count-occurrence-of-unique-values-inside-a-list
from collections import Counter
counts = dict(zip(Counter(foo).keys(), Counter(foo).values()))

[philipc2]

@rytam2

Made a small correction to the second question. I had this before

a = 1
b = 2

But it should of been

a = 1
b = 1

[rytam2]

Question 2: Classes & Attributes

class MyClass:
    foo = "bar"

    def foo():
        return "bar"

MyClass.fooprint = print

1. What does MyClass.foo return? Is it what you expected? Why do you think this is the case? It returns the method foo instead of the attribute foo's value. No but not sure why,

2. What does MyClass.foo() return? It returns the value "bar".

3. What does MyClass.fooprint = print do? Try calling MyClass.fooprint() Create an attribute fooprint under the class MyClass and assigns the function print to the attribute. When MyClass.fooprint() is called, it will print the object in the parenthesis.

[rytam2]

Question 3: CPython & Unexpected Behavior

a = 1
b = 1
print(id(a), id(b)

c = 2024
d = 2024
print(id(c), id(d))

1. What is the id() function doing above? Getting the memory address of the object.

2. What values did you get for a, b, c, and d. a, b returns the same id, but c, d have a unique address respectively.

3. Try the same exercise for values of 255, 256, and 256, -5, and -6 ?

4. Can you explain the behavior you are observing? (You may find this CPython file usefull) Python would reuse the same object for values within [-5,257) Ref: https://stackoverflow.com/questions/53168093/integer-caching-for-numbers-greater-than-256-and-less-than-5