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Discuss the differences between procedural, object-oriented, and functional prog...

Feb 23, 2024

Discuss the differences between procedural, object-oriented, and functional programming paradigms.

The differences between procedural, object-oriented, and functional programming paradigms are fundamental to how programmers structure their code and solve problems.

Procedural Programming

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Focus: It emphasizes a linear top-down approach and a step-by-step method of solving problems

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Example Languages: C, Fortran, and Pascal

Object-Oriented Programming (OOP)

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Focus: It emphasizes encapsulation, inheritance, and polymorphism. Objects are instances of classes, which can hold both data (attributes) and operations (methods)

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Example Languages: Java, C++, and Python

Functional Programming

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Focus: It emphasizes immutability, first-class functions, and higher-order functions

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Example Languages: Haskell, Lisp, and Erlang

Each paradigm has its own set of principles and best use cases, and understanding them helps in selecting the right approach for a given problem.

Traceback (most recent call last): File "/Users/angelcui/Documents/GitHub/PhysioLabXR/physiolabxr/ui/ScriptingGraphicWidget.py", line 70, in add_new_state_widget self.top_spacer = QtWidgets.QSpacerItem(20, 40, QtWidgets.QSizePolicy.Minimum, AttributeError: type object 'QSizePolicy' has no attribute 'Minimum'

It seems like you're encountering an "AttributeError" when trying to use "QSizePolicy.Minimum". This error suggests that the attribute "Minimum" does not exist for the "QSizePolicy" object within the PyQt or PySide framework you are using. In PyQt, the correct usage of "QSizePolicy" should involve using the "QSizePolicy" class with the appropriate policy enum. For example, if you want to set the policy to "Minimum", you should use "QSizePolicy.Minimum" if you're using PyQt4 or "QSizePolicy.Policy.Minimum" if you're using PyQt5. Here's how you might correct the code:

python

Make sure to adjust the import statement according to the version of PyQt you are using (PyQt4, PyQt5, etc.).

Explanation

The AttributeError indicates that the attribute 'Minimum' is not found in 'QSizePolicy'. This could be due to a typo or using the wrong PyQt version. In PyQt5, enums are accessed as 'QSizePolicy.Policy.Minimum', while in PyQt4, it's directly 'QSizePolicy.Minimum'. The provided code snippet is for PyQt5, and you should ensure that your import statements and usage of enums are consistent with the version of PyQt you are using.

####### Q1 - Short Answer ####### What is scope? How does scope work in python? If I create a variable outside a function and inside a function, what happens? ####### Q2 - Pseudocode ####### Write pseudocode for the following problem: Given an input list of integers lst, return True if the list is in increasing order, otherwise return False. ####### Q3 - Python ####### Write Python code for the following problem: Given an input list called input_list, return a new list that only contains the elements that appeared once. For example, given an input list [1, 1, 2, 3, 3, 4, 5, 5] the return values would be [2, 4]. Your code should work properly for an empty list, lists with no duplicates, lists with only duplicates, etc. def unique_elements(input_list): # your code here

# Q1 - Short Answer #

Explanation

Scope

refers to the region in a program where a variable is recognized. In Python, variables that are defined outside of any function are known as

global

variables and are accessible from anywhere in the code after they are defined. Variables that are created inside a function have a

local

scope and can only be accessed within that function. If you create a variable outside a function, it is a global variable, and it can be accessed inside functions. However, if you try to assign a value to a global variable inside a function without declaring it as global, Python will treat it as a new local variable with the same name. To modify a global variable inside a function, you must use the

global

keyword. # Q2 - Pseudocode #

plaintext

Explanation

is_increasing

that takes a list

lst

as input. It first checks if the list is empty or has only one element, in which case it is considered to be in increasing order. Then it iterates through the list, comparing each element with the next one. If any element is greater than or equal to the next, it returns

False

. If the loop completes without finding such a case, it returns

True

. # Q3 - Python #

python

Explanation

unique_elements

that takes an

input_list

as an argument. It uses a dictionary

element_count

to count the occurrences of each element in the list. The

get

method is used to return the current count of the element, defaulting to 0 if the element is not yet in the dictionary, and then incrementing the count. A list comprehension is then used to create a list of elements that have a count of 1, meaning they appear only once in the input list. This list is returned as the result.

What does []+[] returns in javascript? Why does it return that?

In JavaScript, the expression "[]+[]" returns an empty string """".

This happens because the "+" operator in JavaScript is not only used for addition but also for string concatenation.

When the JavaScript engine sees the "+" operator between two arrays, it attempts to convert the arrays to primitives for concatenation.

The process of converting an array to a primitive is to call the "toString()" method on the array.

Since both arrays are empty, their "toString()" method returns an empty string """".

When you concatenate two empty strings, the result is still an empty string.

Therefore, "[]+[]" in JavaScript results in """".