In Python 3.7+ it’s possible to sort a dictionary. Before Python 3.7 dictionaries were unordered and thus you could not sort them. To sort a dictionary in Python: For example, let’s sort a dictionary by values in descending order and print out the sorted values: This gives a following output: This is a comprehensive guide […]
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To access the index in a for loop in Python, use the enumerate() function. For example: Output: This is a quick answer to your question. However, if you are unfamiliar with the syntax, or want to figure out alternative ways to access the index in a for loop, please stick around. In this guide you
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In Python, copying a list can be unintuitive for beginners. This is because you cannot use the assignment operator to take an independent copy of a list. This can be confusing especially for beginner Pythonistas. To create an independent copy of a list in Python, you need to use the copy module’s deepcopy() function like
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To remove an element from a NumPy array: For example: Output: This is the quick answer. However, there is a lot more when it comes to removing elements from a NumPy array. In this guide, you are going to learn how to: How Does numpy.delete() Work In NumPy, there is a built-in function numpy.delete() you
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A NumPy array does not have a built-in append method. Instead, to append elements to a NumPy array, use a separate numpy.append() function. For example: Output: Notice how numpy.append() creates a new copy of the original array. It does not directly append values to it. In this guide, you learn: How to Append to a
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To create an empty NumPy array: For instance, let’s create an empty array with no elements: Output: However, creating an array without elements rarely makes any sense. Instead, you should know and specify the shape of the final array in advance. For instance, let’s create an empty 2D array: Output (contains arbitrary values due to
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In NumPy, -1 in reshape(-1) refers to an unknown dimension that the reshape() function calculates for you. It is like saying: “I will leave this dimension for the reshape() function to determine”. A common use case is to flatten a nested array of an unknown number of elements to a 1D array. For example: But
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In NumPy, the @ operator means matrix multiplication. For instance, let’s multiply two NumPy arrays that represent 2 x 2 matrices: Output: If you are familiar with matrix multiplication, I’m sure this answers your questions. However, if you do not know what matrix multiplication means, or if you are interested in how the @ operator
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To transpose a matrix with NumPy, call the transpose() method. For instance: Output: If you are in a hurry, I’m sure this quick answer is enough. To learn more about matrix transpose, keep on reading. What Is the Transpose of a Matrix The transpose of a matrix is another matrix where the matrix is flipped
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To concatenate two arrays with NumPy: For instance: Output: This is a quick answer. To learn more ways to concatenate arrays and about their efficiency, please, stick around. 4 Ways to Concatenate 1D NumPy Arrays There are four built-in ways to concatenate arrays in NumPy. Before introducing these, it is important you understand that all
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