Hello folks....!!!!
Today we are going to look how to write anonymous functions.
Anonymous functions :
These are nothing but functions without explicit names. They are just one line functions mostly. They are defined with the keyword 'lambda'. Theses functions are assigned to a variable and are called using that variable name. The syntax is :
lambda parameters:expression
Consider a function that returns the (number*4). The parameter passed is the number. Look at the code below
:
This can be written using lambda functions in a simple manner as given
below:
The keyword
lambda is followed by the arguments to be passed, then after a colon(':') the expression to be returned is written. Any kind of expression can
be given in the lambda function. Functions like finding square,cube or
some mathematical expression can be written.
Disadvantages of lambda functions
The main advantage of using these lambda functions is a function can be
passed as an argument to another function. We all know that there are
several built-in functions associated with data structures like lists. One
such function is list.sort(). One of the parameters in this function is
'key', based on which the list should be sorted.
Now consider some record like this :
[(87,'rishav', 10), (90,'akash', 5), (3,'ram', 20),
(45,'gaurav', 15)]
We have to sort this based on the second element (name) in each
tuple inside the list. Let us look at the code now:
We can also generate new iterators based on some conditions.
Now consider two lists:
li1=[45,2,34,1,65,80]
li2=[40,90,33,56,78,30]
Now we need to create a new list which contains the maximum of two
elements at each index of the two lists. For example,
at index '0' - 45>40, so the element 45 from li1 goes into the
new list. Now look at the code below :
In the similar way a list with dictionary can be sorted based on
various keys. For example:
Now the list has been sorted based on the age. Similarly it can be
sorted based on the name also.
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