set: collection
Features: automatic de-duplication feature
s = set () # empty set
s2 = set{'1234445566778'}
print(s2) # ('12345678')
s3 = { '1', '1', '2', '2', '3'}
Intersection
print ( s3 & s2）
print ( s3.intersection(s2))
And Set: a set of two bonded together deduplication
print ( s2 | s3 )
print ( s2.union ( s3 ) )
s4 = {1,2,3}
s5 = {1,4,6}
Difference-set: s4 has set, s5 no set of elements
print （s4 - s5）
print (s4.difference (s5) )
Symmetric difference: remove both the set of common elements
print （s4 ^ s5）
print ( s4.symmetric_diference(s5))
Add elements in the collection:
s4.add ('ss'）
s4.pop () # delete a random element
s4.remove ( 'ss') # delete the specified element
s4.update ({1,2,3}) # to a set further added to the list
lis = [1,1,2,3,4,5,6,8]
for i in lis:
if i%2 != 0:
lis.remove(i)
print (lis) # lis = [1,3,5]
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lis1 = [1,1,2,3,4,5,6,8] # 1 opened up a memory
lis2 = [1,1,2,3,4,5,6,8] # 2 opens a memory
for i in lis2:
if i%2 != 0:
lis1.remove(i)
print(lis1) # lis1 =[1，2,4,6,8]
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lis1 = [1,1,2,3,4,5,6,8]
lis2 = lis1 # Copy shallow, point to the same memory address, the value taken at the same
for i in lis2:
if i%2 != 0:
lis1.remove(i)
print(lis1) # lis1 =[2,4,6,8]
-----------------------------------------------------
lis1 = [1,1,2,3,4,5,6,8]
lis2 = copy.deepcopy (lis1) # deep copy, the other opened a memory
for i in lis2:
if i%2 != 0:
lis1.remove(i)
print(lis1) # lis1 =[2,4,6,8]