Python基础01 集合

初始化

# python3
# coding = utf-8

mylist = []
for item in range(10):
    mylist.append(item * 10 + 3)

myset = set()
for item in range(10):
    myset.add('key{}'.format(item))

mytuple = ()
mytuple = mytuple + (1,)
print(mytuple)
mytuple = mytuple + tuple(mylist)
print(mytuple)

mydict = {}
for item in range(10):
    mydict['key{}'.format(item)] = item

print('dict initialize with -1:')
mydict = {}.fromkeys(('x', 'y'), -1)
print(mydict)

迭代

for item in mylist:
    print(item)

for index in range(len(mylist)):
    print('index:', index, 'item:', mylist[index])

for index, item in enumerate(mylist):
    print('index:', index, 'item:', item)

迭代时删除

mylist[:] = [item for item in mylist if item % 2 == 0]

# remove dict item while iterating
# in python2, just for key in mydict.keys()
for key in list(mydict.keys()):
    if mydict[key] % 2 == 0:
        del mydict[key]

参考文献

Remove items from a list while iterating

How to delete items from a dictionary while iterating over it?