[898] python get the intersection of two lists | union | difference

# method one:
a=[2,3,4,5]
b=[2,5,8]
tmp =[val for val in a if val in b]print(tmp)
#[2,5]

# Method two is much faster than method one!
print list(set(a).intersection(set(b)))

# method one:print(list(set(a+b)))

# Method two is much faster than method one!
print(list(set(a).union(set(b))))

# method one:
tmp =[val for val in b if val not in a] #what is in b but not in a
print(tmp)

# Method two is much faster than method one!
print list(set(b).difference(set(a))) #What is in b but not in a is very efficient!

s =set([3,5,9,10,20,40])      #Create a set of values
t =set([3,5,9,1,7,29,81])      #Create a set of values

a = t | s          #union of t and s,Equivalent to t.union(s)
b = t & s          #the intersection of t and s,Equivalent to t.intersection(s) 
c = t - s          #Difference set (items are in t but not in s),Equivalent to t.difference(s) 
d = t ^ s          #Symmetric difference set (items are in t or s, but will not appear in both),Equivalent to t.symmetric_difference(s)

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