nth Line of Pascal’s Triangle
Question:
Write a program to print the nth line of the Pascal’s Triangle
Program:
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def pascal(n): if n == 1: return [1] else: line = [1] previous_line = pascal(n-1) for i in range(len(previous_line)-1): line.append(previous_line[i] + previous_line[i+1]) line += [1] return line j=int(input("Enter line number:")) print(pascal(j)) |
Explanation:
Pascal’s triangle is a triangle where each number is equal to the sum of the one or two numbers above it:
Output:
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Enter line number: 9 [1, 8, 28, 56, 70, 56, 28, 8, 1] |
Print squares of numbers till 15 (lambda, map, list comprehension)
Question:
Write a single line of code to print squares of numbers till 15 using lambda, map and list comprehension
Program:
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1 |
map(lambda x: x*x, range(15)) |
Explanation:
The lambda operator or lambda function is a way to create small anonymous functions, i.e. functions without a name. These functions are throw-away functions, i.e. they are just needed where they have been created. Lambda functions are mainly used in combination with the functions filter(), map() and reduce().
The map function is the simplest one among Python built-ins used for functional programming. These tools apply functions to sequences and other iterables. The filter filters out items based on a test function which is a filter and apply functions to pairs of item and running result which is reduce.
So here the output of the anonymous function for squaring x when x ranges from 1 to 15 is recieved.
Output:
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1 |
=> [0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196] |
Program using Lambda Function
Question:
Consider variable x. do the following operation. Add 2 to x and square the result. Again add 3 to x and square the result. Do using anonymous functions in python
Program:
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def func(n): return lambda x: (x+n)**2 #b is the lambda function where n = 2 and it accepts an arguement x b=func(2) print "b is a lambda function with n = 2 and type : ",type(b) #b is of the type 'function' what ever value is passed to it is #passed as x of the lambda function print "\npassing value 5 to function b and result is : ", print (b(5)) #here 5 is passed to x of lambda function c=func(3) print "\n\n\nc is a lambda function with n = 3 and type : ",type(c) print "\npassing value 5 to function c and result is : ", print (c(5)) b=5 print "\n\n\nb is now an integer with value : ",b c=4.5 print "\nc is now a float with value : ",c |
Explanation:
The lambda operator or lambda function is a way to create small anonymous functions, i.e. functions without a name. These functions are throw-away functions, i.e. they are just needed where they have been created. Lambda functions are mainly used in combination with the functions filter(), map() and reduce().
Output:
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<span class="">b is a lambda function with n = 2 and type : <class 'function'> passing value 5 to function b and result is : 49 c is a lambda function with n = 3 and type : <class 'function'> passing value 5 to function c and result is : 64 b is now an integer with value : 5 c is now a float with value : 4.5</span> |