python22-数据遍历

# 1.遍历字典
d = {'a': 1, 'b': 2, 'c': 3, 'd':3}
'''
# 1.1遍历所有键
for key in d:
    print(key)

for key in d.keys():
    print(key)

# 1.2遍历所有值
for value in d.values():
    print(value)

# 1.3遍历所有的键-值对
for key, value in d.items():
    print(key, value)

# 1.4使用字典推导式
d_inverted = {value: key for key, value in d.items()}
print(d_inverted)
'''

# 2.列表遍历
my_list = [1, 2, 3, 4, 5]
'''
# 2.1 for 循环遍历
for item in my_list:
    print(item)
for i in range(len(my_list)):
    print(my_list[i])

# 2.2 while循环遍历
i = 0
while i < len(my_list):
    print(my_list[i])
    if my_list[i] == 3:
        my_list.pop(i)
        i -= 1
    i += 1

# 2.3列表推导式
new_list = [item * 2 for item in my_list]
print(new_list)
'''