human
Print all possible combinations of r elements in a given array of size n | The main function that prints all combinations of size r in arr [ ] of size n . This function mainly uses combinationUtil ( ).
A temporary array to store all combination one by one.
Print all combination using temprary array 'data[]  .
arr [ ] -- -> Input Array data [ ] -- -> Temporary array to store current combination start & end -- -> Staring and Ending indexes in arr [ ] index -- -> Current index in data [ ] r -- -> Size of a combination to be printed.
Current combination is ready to be printed , print it.
replace index with all possible elements . The condition " end - i + 1 ▁ > = ▁ ▁ r - index " makes sure that including one element at index will make a combination with remaining elements at remaining positions.
Driver Code"
How can the above be solved in Python?
 What is a code to print all possible combinations of r elements in a given array of size n and the other steps required?
assistant
#Here is code to print all possible combinations of r elements in a given array of size n and the other steps required.
 def printCombination ( arr , n , r ) :
	data = [ 0 ] * r ;
	combinationUtil ( arr , data , 0 , n - 1 , 0 , r ) ;
def combinationUtil ( arr , data , start , end , index , r ) :
	if ( index == r ) :
		for j in range ( r ) :
			print ( data [ j ] , end = " ▁ " ) ;
		print ( ) ;
		return ;
	i = start ;
	while ( i <= end and end - i + 1 >= r - index ) :
		data [ index ] = arr [ i ] ;
		combinationUtil ( arr , data , i + 1 , end , index + 1 , r ) ;
		i += 1 ;
arr = [ 1 , 2 , 3 , 4 , 5 ] ;
r = 3 ;
n = len ( arr ) ;
printCombination ( arr , n , r ) ;