Modifying / extracting multiple list items simultaneously using variable from range

[ehammarlund]

I am a beginner(**) trying to figure out how to put multiple items in/out of lists using variables. To demonstrate, I'm trying to make a prime sieve. [u]My comments/questions bolded below.

highnum=1000000 #the number you’re checking to, here it's a million, could be anything
erik=list(range(1,highnum) #create a list to sieve it
def sieve(x):
	erik[(2x)::x]=False # 

I CAN’T FIGURE OUT HOW TO ASSIGN MULTIPLE LIST VALUES AT THE SAME TIME. CAN IT BE DONE? It doesn’t seem to want to accept a variable in the list definition so perhaps not…?

I ALSO TRIED:

erik.insert[(2x)::x]=False

THAT DID NOT WORK EITHER. SIGH.

IF I CAN GET IT TO WORK, THEN IN THEORY I CAN DO THIS:

for y in range (1,((highnum/2)+1)):
	sieve(y)
sieveoutput=(Erik[] where erik!= False)

#WILL THIS WORK/WHY WON’T THIS WORK? HELP!

OR DO I NEED TO DO IT LIKE THIS?

For z in range(1,highnum):
	iferik(z) != False:
		sieveoutput.append erik[z]

Sorry about the very low-level questions;I literally started to learn Python three days ago. Thanks in advance for any pointers.