Python Using Lists, Dictionaries, and Sets, Python sequence objects (such as lists) are iterable and have other characteristics that make them instantiated iterable objects. In the previous example, the tuple() function was used to collect the output of a generator…
Python Conditional Expression Evaluation. Python enforces strict ordering of expressions, with the notable exception of the short-circuiting operators and and or. Statements are also evaluated in a strict order, making them difficult to optimize because they might violate the strict…
Python Using real-number arguments for counting. The count() function accepts non-integer arguments. You can define expressions like count(0.5, 0.1) to provide floating-point numbers. If the step value doesn’t have a suitable representation, cumulative errors will occur. It’s best to use…
Python Lazy Evaluation. Functional programming is efficient because it defers computation until it’s needed. Lazy (also known as “non-strict”) evaluation is very important, and Python has built-in support for it. In Python, the logical operators and, or, and if-then-else are…
Python Function Classification. Functions can be roughly divided into the following two categories. Scalar functions: These functions act on a single value and return a single value. Examples include abs(), pow(), and functions in the entire math module. Collective functions:…
Python Defining Web Services as Functions Here’s a REST-based web service that slices data and provides downloads in JSON, XML, or CSV formats. We’ll provide a fully WSGI-compliant wrapper. The functions that perform the actual work of the application don’t…
Other Features of Monads Another feature of PyMonad is the confusingly named monoid. Originating from mathematics, it refers to a set of data elements with operators and an identity element, and this set of data elements is closed with respect…
Python uses relaxed dictionary rules. Before Python 3.6, the order of dictionary keys was not defined. If you try to create a dictionary with multiple items that share the same key value, the resulting dict object will only retain one…
Python HTTP Request-Response Model. The HTTP protocol is almost stateless, meaning that the server provides a response after the user agent (or browser) issues a request. For services that do not involve cookies, client programs can handle the protocol from…
Python Combining Multiple Iterators with chain() You can use the chain() function to combine multiple iterators into a single iterator, such as recombining data that was separated by the groupby() function. For simple collections, this method can be used to…