Instead, a much better way of doing the same thing is to use list comprehension: List comprehension is dead simple when you know the formula. It starts with the keyword lambda, followed by a comma-separated list of zero or more arguments, followed by the colon and the return expression. However, since there is only one expression, it theoretically is a one-liner function. find (phrase [::-1]) 3 4 # Swap Two Variables Python One-Liner 5 a, b = b, a 6 7 # Sum Over Every Other Value Python One-Liner 8 sum (stock_prices [:: 2]) 9 10 # Read File Python One-Liner 11 [line. Thankfully, Python realizes this and gives us an awesome tool to use in these situations. they are just needed where they have been created. The reduce function will continually apply a lambda function until only a single value is returned. functions without a name. 1 # Palindrome Python One-Liner 2 phrase. Do you want to become a code master by focusing on practical code projects that actually earn you money and solve problems for people? Before looking at a lambda function, let’s look at a super basic function defined the “traditional” way: Here is a simple function that doubles the passed value. His passions are writing, reading, and coding. Simple for loops can be written using list comprehension. Using if else in lambda function is little tricky, the syntax is as follows, lambda : if else Here’s the one-liner expression that accomplishes this without the lambda function: You can try this example yourself in our interactive code shell: Let’s dive into some background information in case you wonder how list comprehensions work. Related Article: Python One Line For Loop. Syntax of Lambda function lambda arguments: expression. Lambda functions are a Pythonic way of writing simple functions in a single line. With the help of the lambda function, we can take n number of arguments, but there will be only one expression. I’ll call the lambda syntax itself a lambda expression and the function you get back from this I’ll call a lambda function. You can define functions with lambda expressions. The reduce function replaces the first two elements of a list with the product of those two elements. list (map (lambda i: i**2, range (2, 10))) Output [4, 9, 16, 25, 36, 49, 64, 81] List comprehension is performing a loop operation and then combines items to a list in just a single line of code. Committed to all work being performed in Free and Open Source Software (FOSS), and as much source data being made available as possible. ( Log Out /  But you can also use a more complex expression such as x.upper(). The lambda operator or lambda function is a way to create small anonymous functions, i.e. You can also achieve this using a functional programming construct called currying. Using lambda function. Some see list comprehensions as more Pythonic than map, filter and reduce. You will see all this in action in the upcoming examples. [Rows]. Change ), You are commenting using your Google account. Check out our 10 best-selling Python books to 10x your coding productivity! If you’re like most programmers, you know that, eventually, once you have an array, you’re gonna have to write a loop. Python supports lambda's. You can join his free email academy here. The map command generates a ’map object’. “A list comprehension consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses. The rangefunction returns a new list with numb… Here is an example where filter is used to return even numbers from a list. In Python, there is not C like syntax for(i=0; i