nasturtus · May 2, 2017 03:53
diff --git a/generator_list.py b/generator_list.py
 # Generators vs List Comprehension
 # References:
 # 1. https://pythonprogramming.net/list-comprehension-generators-intermediate-python-tutorial/
 # 2. The following is from reuven@lerner.co.il:
 # That's why using a generator expression, which acts as an iterator, is often such an attractive option in Python: 
 # Rather than waiting for the entire thing to execute, and then returning a large list, we return the instructions 
 # that create a new list.  In doing so, we save memory and execution time, allowing x to get something back faster.
 # The fact that creating a generator expression is often just a matter of replacing the square brackets ( '[' and ']' )
 # with regular parentheses ( '(' and ')' ) makes it a no-brainer in many situations.

 x = (i for i in range(100)) # returns generator object, not the range of nos.
 print(list(x)) # needs casting to a list in order to get the range of nos.
 print()
 xx = (i for i in range(100) if i % 2 == 0) # returns generator of even nos. with the exception of '0'
 print(list(xx)) # needs casting to a list in order to get the range of nos.
 print()
 y = [i for i in range(100)] # returns ready list populated with the range of nos.
 print(y)
 print()
 yy = [i for i in range(100) if i % 3 == 0] # returns generator of odd nos. with the exception of '0'
 print(yy)
	# Generators vs List Comprehension
	# References:
	# 1. https://pythonprogramming.net/list-comprehension-generators-intermediate-python-tutorial/
	# 2. The following is from reuven@lerner.co.il:
	# That's why using a generator expression, which acts as an iterator, is often such an attractive option in Python:
	# Rather than waiting for the entire thing to execute, and then returning a large list, we return the instructions
	# that create a new list. In doing so, we save memory and execution time, allowing x to get something back faster.
	# The fact that creating a generator expression is often just a matter of replacing the square brackets ( '[' and ']' )
	# with regular parentheses ( '(' and ')' ) makes it a no-brainer in many situations.

	x = (i for i in range(100)) # returns generator object, not the range of nos.
	print(list(x)) # needs casting to a list in order to get the range of nos.
	print()
	xx = (i for i in range(100) if i % 2 == 0) # returns generator of even nos. with the exception of '0'
	print(list(xx)) # needs casting to a list in order to get the range of nos.
	print()
	y = [i for i in range(100)] # returns ready list populated with the range of nos.
	print(y)
	print()
	yy = [i for i in range(100) if i % 3 == 0] # returns generator of odd nos. with the exception of '0'
	print(yy)