python学习·第七天

推导式的学习

# 依次加入列表里
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
list1 = []
i = 0
while i < 10:
    list1.append(i)
    i += 1
print(list1)

list2 = []
for i in range(10):
    list2.append(i)
print(list2)

list3 = [i for i in range(10)]
print(list3)

# 要求是键是1-5 值是它的平方
# {1: 1, 2: 4, 3: 9, 4: 16}
dict1 = {}
for i in range(1, 5):
    dict1[i] = i ** 2
print(dict1)
# {1: 1, 2: 4, 3: 9, 4: 16}
dict2 = {i: i ** 2 for i in range(1, 5)}
print(dict2)
# {'1': '4', '2': '5', '3': '6'}
name1 = ["1", "2", "3"]
name2 = ["4", "5", "6"]
dict3 = {name1[i]: name2[i] for i in range(len(name1))}
print(dict3)
# {'1': '4', '2': '5', '3': '6'}
name3 = ["1", "2", "3"]
name4 = ["4", "5", "6"]
dict4 = {}
for i in range(len(name3)):
    dict4[name3[i]] = name4[i]
print(dict4)

# [0, 2, 4, 6, 8]
# [0, 2, 4, 6, 8]
# [1, 3, 5, 7, 9]

list1 = [i for i in range(0, 10, 2)]
print(list1)

list2 = [i for i in range(10) if i % 2 == 0]
print(list2)

list3 = [i for i in range(10) if i % 2 == 1]
print(list3)

list1 = [1, 2, 3]
set1 = set()
for i in list1:
    set1.add(i ** 2)
print(set1)  # {1, 4, 9}

set2 = {i ** 2 for i in list1}
print(set2)  # {1, 4, 9}