Podcast
Questions and Answers
What will the output of a.sum(axis=0)
be for the array a = [[1, 2, 3, 4], [5, 6, 7, 8]]
?
What will the output of a.sum(axis=0)
be for the array a = [[1, 2, 3, 4], [5, 6, 7, 8]]
?
Which function would you use to find the maximum element in a NumPy array along a specific axis?
Which function would you use to find the maximum element in a NumPy array along a specific axis?
Which of the following methods would return the standard deviation of an entire NumPy array if no axis is specified?
Which of the following methods would return the standard deviation of an entire NumPy array if no axis is specified?
What does the lstsq()
function in NumPy's linalg submodule return?
What does the lstsq()
function in NumPy's linalg submodule return?
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What will the output of np.linalg.solve(A, b)
be for the given matrices if A
is invertible?
What will the output of np.linalg.solve(A, b)
be for the given matrices if A
is invertible?
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Which function is used to compute the dot product of two matrices in NumPy?
Which function is used to compute the dot product of two matrices in NumPy?
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What is the purpose of the inv()
function in the linalg submodule?
What is the purpose of the inv()
function in the linalg submodule?
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Which function would you use to compute the eigenvalues and eigenvectors of a given matrix in NumPy?
Which function would you use to compute the eigenvalues and eigenvectors of a given matrix in NumPy?
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If A
is a square matrix, what does the det()
function compute?
If A
is a square matrix, what does the det()
function compute?
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What will happen if argmax()
is called on a NumPy array?
What will happen if argmax()
is called on a NumPy array?
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What happens when a value in a view array is modified?
What happens when a value in a view array is modified?
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How can you determine if an array is a view?
How can you determine if an array is a view?
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Which method can be used to create a copy of a view array?
Which method can be used to create a copy of a view array?
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Which of the following operations does not create a view?
Which of the following operations does not create a view?
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What will the line 'v = M[0,:]' return?
What will the line 'v = M[0,:]' return?
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What does the expression 'M.base' return if M is an original array?
What does the expression 'M.base' return if M is an original array?
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Which of the following correctly demonstrates changing a view without altering the original array?
Which of the following correctly demonstrates changing a view without altering the original array?
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When comparing arrays with '==' operator, what is a requirement for the arrays?
When comparing arrays with '==' operator, what is a requirement for the arrays?
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Which of the following best describes an array view?
Which of the following best describes an array view?
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What are functions that act element-wise on NumPy arrays called?
What are functions that act element-wise on NumPy arrays called?
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Which function would give you the ceiling values of a NumPy array?
Which function would give you the ceiling values of a NumPy array?
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Using the vectorize decorator in NumPy allows you to convert which type of function?
Using the vectorize decorator in NumPy allows you to convert which type of function?
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What does the np.tan function do when applied to an array?
What does the np.tan function do when applied to an array?
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What would be the result of using np.exp on the array [1, 2, 3]?
What would be the result of using np.exp on the array [1, 2, 3]?
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Which of the following functions will convert an array to its floor values?
Which of the following functions will convert an array to its floor values?
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The output of np.round([1.5, 2.5, 3.5])
will be?
The output of np.round([1.5, 2.5, 3.5])
will be?
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Which of the following is an example of a universal function in NumPy?
Which of the following is an example of a universal function in NumPy?
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Flashcards
Universal Functions in NumPy
Universal Functions in NumPy
Universal functions in NumPy operate element-wise on arrays, applying the same function to each element. They are essential for performing mathematical operations efficiently on entire arrays.
Pre-Defined Universal Functions
Pre-Defined Universal Functions
NumPy provides a wide variety of pre-defined universal functions, including trigonometric functions (cos, sin, tan), exponential functions (exp), logarithms (log), rounding functions (ceil, floor, round), and many more.
Creating Your Own Universal Functions
Creating Your Own Universal Functions
You can create your own universal functions in NumPy using the vectorize
function. This allows you to apply any Python function to each element of a NumPy array.
The vectorize
Decorator
The vectorize
Decorator
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NumPy Array Views
NumPy Array Views
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Boolean Arrays
Boolean Arrays
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Array Indexing
Array Indexing
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Advanced Array Indexing
Advanced Array Indexing
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sum(a, axis=None)
sum(a, axis=None)
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min(a, axis=None)
min(a, axis=None)
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prod(a, axis=None)
prod(a, axis=None)
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argmax(a, axis=None)
argmax(a, axis=None)
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argmin(a, axis=None)
argmin(a, axis=None)
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sort(a, axis=-1)
sort(a, axis=-1)
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argsort(a, axis=-1)
argsort(a, axis=-1)
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numpy.linalg
numpy.linalg
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numpy.linalg.solve(A, b)
numpy.linalg.solve(A, b)
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numpy.linalg.svd(a)
numpy.linalg.svd(a)
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Invertible matrices
Invertible matrices
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Least Squares Method ('lstsq')
Least Squares Method ('lstsq')
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Array View
Array View
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Array 'base' Attribute
Array 'base' Attribute
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Slicing Arrays
Slicing Arrays
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Reshaping and Transpose
Reshaping and Transpose
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Copying Array Views
Copying Array Views
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Array Comparisons
Array Comparisons
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Broadcastable Arrays
Broadcastable Arrays
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Study Notes
NumPy Arrays
- NumPy arrays (ndarrays) offer various methods for operations on arrays, including mathematical functions.
- Universal functions (ufuncs) operate element-wise on arrays; many are already defined in NumPy (e.g.,
cos
,tan
,exp
,log
,ceil
,floor
,round
).
Creating Universal Functions
- Python functions can be converted into universal functions using
np.vectorize
. - Alternatively, a decorator
@np.vectorize
can be applied directly above the function definition.
Array Methods
- NumPy arrays (
ndarray
) have methods for specific operations (e.g.,sum
,min
,max
,mean
,std
,prod
). - These methods often operate along a specified axis.
- Function equivalents with the same name typically exist within the NumPy module. For instance, the sum function can also calculated by ndarray.sum()
Linear Algebra Functions
- NumPy's
linalg
submodule provides linear algebra operations. - The
solve
function can solve systems of equations with invertible matrices ($Ax = b$). - For non-invertible matrices,
lstsq
(least squares) minimizes the square error.
Array Views
- Array views share data with the original array.
- Changes in a view affect the original array.
- The
base
attribute of an array can distinguish between original arrays and views. - Operations like reshaping and transposing make views of the original array.
Boolean Operations
- Boolean operations on arrays yield boolean arrays (e.g., comparisons using operators like
==
,!=
,<
,>
). - The
all
function checks if all elements are True;any
checks if at least one element is True.
Integer Array Indexing
- Integer arrays select elements from arrays;
- Colons (:) in indices access all elements in the corresponding dimension.
Boolean Array Indexing
- Boolean array indexing selects elements based on a boolean condition.
- Boolean selection can be applied on multiple dimensions using boolean arrays with dimensions that correspond to the array shape.
Assignment by Array Indexing
- The selected elements in arrays using indexing can be updated with new values (broadcastable).
The where
Function
np.where(condition, x, y)
can choose elements based on a condition.- If x and y are not given, the function returns indices where a condition is True.
- If both x and y are given, the output returns values from x where a condition is True and y otherwise.
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Description
This quiz covers essential concepts related to NumPy arrays, including their creation, universal functions, array methods, and linear algebra functions. Test your understanding of how to perform various mathematical operations using NumPy and its capabilities for handling array data effectively.