ChrisProblem Formulation Assuming you have the Python package manager pip installed in your operating system (Windows, Linux, macOS). How to check the version of a package with pip? Method 1: pip show To check which version of a given package is installed, use the pip show <your_package> command. For example, to check the version of … Read more
Can you spot the outliers in the following sequence: 000000001000000001? Detecting outliers fast can be mission critical for many applications in military, air transport, and energy production. This article shows you the most basic outlier detection algorithm: if an observed value deviates from the mean by more than the standard deviation, it is considered an … Read more
Problem Formulation Recap: The Python string.split(separator) method splits the string at a given separator and returns a split list of substrings. Per default, it uses arbitrary whitespace as a separator. Thus, if you want to store the result in a list variable, you can simply do so: However, what if you’d rather want to store … Read more
Problem Formulation Given a Python dictionary d, and a list of dictionary keys. How to best determine the list of values associated to the keys? Formally, for each key in the input list, you want to add d[key] to the list of values. Here’s a minimal example: # Input: d = {‘alice’: 18, ‘bob’: 24, … Read more
To filter a list in Python, you can use the built-in filter() function. The first argument is the filtering condition, defined as a function. This filtering condition function is often dynamically-created using lambda functions. The second argument is the iterable to be filtered—the lambda function checks for each element in the iterable whether the element … Read more
If you use multiple operators in a single expression, the semantics of that expression depends on the assumed operator precedence. For example, consider the expression 2 + 4 * 0. Does Python calculate (2 + 4) * 0 or 2 + (4 * 0)? Depending on the operator precedence, the result would be 0 or … Read more
The np.sort(array) function returns a sorted copy of the specified NumPy array. Per default, it sorts the values in ascending order, so np.sort([42, 2, 21]) returns the NumPy array [2 21 42]. Here’s an example of 1D sorting: And here’s an example of 2D sorting — each axis is sorted separately. An example of 3D … Read more
Python “in” Operator – Checking Membership Example
NumPy slice assignment allows you to use slicing on the left-hand side of an assignment operation to overwrite a specific subsequence of a NumPy array at once. The right side of the slice assignment operation provides the exact number of elements to replace the selected slice. For example, a[::2] = […] would overwrite every other … Read more
Python “in” Operator – Checking Membership Example
The Python is not operator — consisting of two keywords is and not — tests if the left and right operands refer to a different object—in which case it returns True. It returns False if they refer to the same object. For example, the expression [1, 2, 3] is not [1, 2, 3] returns True … Read more
The Python is keyword tests if the left and right operands refer to the same object—in which case it returns True. It returns False if they are not the same object, even if the two objects are equal. For example, the expression [1, 2, 3] is [1, 2, 3] returns False because although both lists … Read more