Conceived in the late 1980s, Python Language grew to be one of the dominating developing tool in the industry. Because of its elegance and simplicity, Python is used in areas like Web Development, Data Science, Machine Learning Frameworks, and even Video Game Development.
Even with its versatility and plain syntax, learners keep away from some basic yet powerful functions Python offers. In this article, we will dive into those underrated function, beginners shy away from.
The map() function
Before we start carefully see the terminologies to understand the working of map() function.
- Iteration is a general computer science term; it refers to performing an action to a set of elements, one element at a time. An excellent example is a loop.
- An iterator is an object that represents a stream of data; it returns the data one element at a time. It also remembers its position during iteration.
- Iterable is an object that we can loop over (e.g. a string, a list, or a file). From the Iterable*, we get the **iterator**.*
map() function returns a map object of the results after applying the function to each item of a given iterable (list, tuple, etc.). If additional iterable arguments are passed, the function must take that many arguments and applies to the items from all iterables in parallel.
With multiple iterables, the iterator stops when the shortest iterable is exhausted. Maps are iterable, just like lists and tuples, so we can use a for loop to look at all the values in the map.
- map: A processing pattern that traverses a sequence and performs an operation on each element.
- mapping: A relationship in which each element of one set corresponds to an element of another set.
Syntax
map(fun, iter)
#Parameters
#fun: Function to which map passes each element of iterable.
#iter: It is an iterable which is to be mapped.
Without
map()we’d be forced to write complex code to “loop” the function over a number of items.
Example
#Cacluate Square of a Number
def calculateSquare(n):
return n*n
numbers = (1, 2, 3, 4)
result = map(calculateSquare, numbers)
print(result)
# converting map object to set
numbersSquare = set(result)
print(numbersSquare)
Lambda
Lambda is Python’s way of creating anonymous functions. These are the same as other functions, but they have no name. The goal is to be simple or short-lived and it’s easier just to write out the function in one line instead of going to the trouble of creating a named function. Lambdas are much more limited than full function definitions. But I think they’re very useful for simple little data cleaning tasks.
Syntax
lambda arguments: expression
You declare a lambda function with the word lambda followed by a list of arguments, followed by a colon and then a single expression and this is key. Then return the expression value on the execution of the lambda. There’s only one expression to be evaluated in a lambda.
Note that you can’t have default values for lambda parameters and you can’t have complex logic inside of the lambda itself because you’re limited to a single expression.
Example
- Without using Lambda: The identity function, a function that returns its argument, is expressed with a standard Python function definition using the keyword def as follows:
def identity(x):
return x
- Using Lambda: Lambda definition does not include a “return” statement, it always contains an expression that is returned. In contrast, if you use a Python lambda construction, you get:
lambda x: x
We can use lambda functions along with built-in functions like filter(), map() and reduce().
- Use of lambda() with filter(): The filter() function in Python takes in a function and a list as arguments. This offers an elegant way to filter out all the elements of a sequence.
- Use of lambda() with map(): The map() function in Python takes in a function and a list as an argument.
- Use of lambda() with reduce(): The reduce() function in Python takes in a function and a list as an argument.
Conclusion
After reading this article I hope you got the idea of Map() and Lambda functions, they are normally overlooked by programmers. To beginners, I would suggest that you must master these functions because it would definitely help you in the long run. Knowing the ins-outs of the language you are working in will empower you to program like an artisan. These were just a handful of things I thought were worth sharing. Happy coding!