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Questions and Answers
Which library is primarily used for numerical analysis in Python?
Which library is primarily used for numerical analysis in Python?
NumPy allows for efficient computations with large multi-dimensional arrays.
NumPy allows for efficient computations with large multi-dimensional arrays.
True (A)
What is the time taken by np.sum() to sum 10 million numbers?
What is the time taken by np.sum() to sum 10 million numbers?
0.0009 seconds
Scikit-learn is built on top of ___.
Scikit-learn is built on top of ___.
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Match the following Python libraries with their primary functions:
Match the following Python libraries with their primary functions:
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What is a key feature of NumPy?
What is a key feature of NumPy?
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What Python shortcut is used for importing the NumPy library?
What Python shortcut is used for importing the NumPy library?
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What method is used to calculate the total in the provided code snippet?
What method is used to calculate the total in the provided code snippet?
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Broadcasting in NumPy allows operations between arrays of different shapes without any issues.
Broadcasting in NumPy allows operations between arrays of different shapes without any issues.
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Name one mathematical operation that is considered an aggregation.
Name one mathematical operation that is considered an aggregation.
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The result of multiplying array X by array a is ____, where X is np.array([[1,2,3],[4,5,6]]) and a is np.array([0,1,0]).
The result of multiplying array X by array a is ____, where X is np.array([[1,2,3],[4,5,6]]) and a is np.array([0,1,0]).
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Match the following aggregation functions with their description:
Match the following aggregation functions with their description:
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What error occurs when trying to add two arrays of differing shapes without appropriate reshaping?
What error occurs when trying to add two arrays of differing shapes without appropriate reshaping?
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The output of reshaping an array to (2,2) with elements [0, 10, 20, 30] will be an array containing two rows and two columns.
The output of reshaping an array to (2,2) with elements [0, 10, 20, 30] will be an array containing two rows and two columns.
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What is the result of the operation x.reshape((4,1)) when x = np.array([0,10,20,30])?
What is the result of the operation x.reshape((4,1)) when x = np.array([0,10,20,30])?
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The total of outer product can be calculated using the formula: total = σ_{i=1}^{n} x_i ⋅ σ_{j=1}^{m} y_j or using _____ instead of for-loops.
The total of outer product can be calculated using the formula: total = σ_{i=1}^{n} x_i ⋅ σ_{j=1}^{m} y_j or using _____ instead of for-loops.
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Match the following operations with their result:
Match the following operations with their result:
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What does the expression A[0, :] return?
What does the expression A[0, :] return?
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A slicing operation of the form A[0:2] returns the first two elements of a matrix.
A slicing operation of the form A[0:2] returns the first two elements of a matrix.
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What is the output of the expression x[:, 1] when x is defined as np.array([[3,2,1], [4,5,6]])?
What is the output of the expression x[:, 1] when x is defined as np.array([[3,2,1], [4,5,6]])?
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The expression x[x > 2] extracts elements from the array x that are greater than ___ .
The expression x[x > 2] extracts elements from the array x that are greater than ___ .
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Match the following expressions with their corresponding outputs:
Match the following expressions with their corresponding outputs:
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What is the output of the expression x[::-1, [2,1,0]] for the array x defined as np.array([[6,5,4], [1,2,3]])?
What is the output of the expression x[::-1, [2,1,0]] for the array x defined as np.array([[6,5,4], [1,2,3]])?
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Boolean indexing works with both NumPy arrays and regular Python lists.
Boolean indexing works with both NumPy arrays and regular Python lists.
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What shape does the expression A[:, :2] return when A is defined as np.array([[0,1,2], [3,4,5]])?
What shape does the expression A[:, :2] return when A is defined as np.array([[0,1,2], [3,4,5]])?
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What function is used to sort an array in ascending order?
What function is used to sort an array in ascending order?
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The command np.sort(-a) sorts an array in ascending order.
The command np.sort(-a) sorts an array in ascending order.
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What value of x produces the minimum of cos(x) between [0, 6]?
What value of x produces the minimum of cos(x) between [0, 6]?
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The function used to generate random numbers uniformly is np.random.______
The function used to generate random numbers uniformly is np.random.______
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Match the following NumPy functions with their description:
Match the following NumPy functions with their description:
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Which of the following statements about direct sorting is correct?
Which of the following statements about direct sorting is correct?
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Np.random.rand(N) and np.random.randn(N) produce the same type of random numbers.
Np.random.rand(N) and np.random.randn(N) produce the same type of random numbers.
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To find the maximum value in an array, you would use the function np.max(______).
To find the maximum value in an array, you would use the function np.max(______).
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What does A[A > 2] return when A is defined as np.array([[0,3,1], [4,2,5]])?
What does A[A > 2] return when A is defined as np.array([[0,3,1], [4,2,5]])?
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Creating a slice of a NumPy array results in a copy of the original array.
Creating a slice of a NumPy array results in a copy of the original array.
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What operation does A * 2 perform on the NumPy array?
What operation does A * 2 perform on the NumPy array?
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In NumPy, A.copy() creates a __________ of the array A.
In NumPy, A.copy() creates a __________ of the array A.
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Match the following functions with their descriptions:
Match the following functions with their descriptions:
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What will happen if you execute B[0, 0] = 10 after creating B via B = A.copy()?
What will happen if you execute B[0, 0] = 10 after creating B via B = A.copy()?
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Element-wise operations like A + B perform matrix multiplication in NumPy.
Element-wise operations like A + B perform matrix multiplication in NumPy.
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In the given context, how are gains calculated when $X_{tj} > 0$?
In the given context, how are gains calculated when $X_{tj} > 0$?
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Study Notes
Course Information
- Course title: Programming Python for Business Analytics
- Course code: BMAN737
- Week: 3, Lecture 2
- Topic: Numerical Analysis
Instructor Information
- Professor: Manuel López-Ibáñez
- Email: [email protected]
- Office hours: Monday 4pm-5pm, Friday 9am-10am
- Contact: Discussion board in Blackboard, Calendly link provided
Numerical Analysis (NumPy)
- Overview: Week 3 lecture focuses on numerical analysis using NumPy.
New Material
- Moving from basic to advanced analytics
- Complete Python code available in Blackboard
- Labs: shift towards case studies
Course Plan
- Week 3: Numerical Analysis (NumPy)
- Week 4, Lecture 1: Data Exploration and Visualization (Pandas + Matplotlib)
- Week 4, Lecture 2: Data preprocessing and preparation (Pandas + Scikit-learn)
- Week 5: Machine learning (Scikit-learn)
Part 1: Vectors and Matrices
- Focus of initial portion of the lecture
Part 2: Broadcasting
- Lecture topic
Part 3: Aggregations and Operations
- Further lecture topic
NumPy Arrays
- NumPy arrays differ from lists (e.g., appending an element to a NumPy array, will not add to the array but return a new array).
- NumPy arrays support fast calculations
- NumPy arrays are multi-dimensional (vectors and matrices)
- Includes good integration with Pandas & Matplotlib
NumPy Arrays vs. Lists
- NumPy arrays are different from Python lists
- Using NumPy arrays for data structure and analysis will be much faster than using Python lists for identical operations.
- Operations on NumPy arrays are element-wise by default.
NumPy Array Indexing
- NumPy array indexing differs from list indexing, and uses square bracket notation.
NumPy Slices
- NumPy slices are views, not copies. This means changes made to a slice will modify the original array
NumPy Slices Explained
- Slices are not copies of arrays, but rather views to the same underlying data. This is an important concept to understand when working with NumPy arrays.
- Modifying a NumPy slice affects the original array.
- Use
.copy()to create a true copy.
NumPy Arrays: Indexing
- Different ways to index arrays
- Examples shown for accessing specific elements or subsets.
Broadcasting
- Operators (+,-,*,/) usually act element-wise on arrays
- Can calculate across matrices, or arrays of different dimensions if dimensions align.
- ValueError error if NumPy cannot broadcast correctly.
- Reshaping an array can help with broadcasting when shapes are not matching
Recap
- NumPy arrays are specialized data structures capable of numerous mathematical and statistical operations
- NumPy provides specialized functions for sorting.
- NumPy provides direct sorting and indirect sorting.
- NumPy and SciPy are utilized for complex calculations and mathematical functions, respectively.
Broadcasting Examples
- Matrix and vector calculations
- Using reshape to enable broadcasting
- Common error scenarios
Aggregations
- Operations like sum, min, max, mean, all, any are aggregations (reductions),
- Used along axis 0 or axis 1 of an array
SciPy Library
- Library for numerical analysis and scientific computations
- Includes sub-modules such as optimize, linalg, and stats
- Provides useful mathematical and statistical functions
Next Week Material
- Libraries: pandas and matplotlib
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Description
This quiz covers the Week 3 lecture focusing on numerical analysis using NumPy in the Programming Python for Business Analytics course. It includes topics such as vectors, matrices, and broadcasting concepts essential for moving towards advanced analytics. Prepare to apply your knowledge to real-world case studies and strengthen your understanding of Python programming.
