for cycle day 006

Process for the control of a loop

Loop: Repeat (according to some law) to do one thing

lt = [1, 2, 3, 4]
ind = 0
while True:
    print(lt[ind])
    ind += 1

while loop: everything can be recycled
for loop: provide a means, do not rely on the value of the index

dic = {'a': 1, 'b': 2, 'c': 3}
for i in dic:
    print(i,dic[i])

'' '
For the variable name (will get a value of each element of the container class, it is not the end of the cycle) in the container-earth element:
Print (variable name)
' '

lt = [1, 2, 3, 4]
for i in lt:
    print(i)

dic = {'a': 1, 'b': 2, 'c': 3}
count = 0
for i in dic:  # 对于字典，for循环只能拿到key
    print(i, dic[i])
    print(count)
    count += 1

print(list(range(10)))  # 循环得到列表

for i in range(50,101):  # 顾头不顾尾
    print(i)
for i in range(50,101,3):  # 顾头不顾尾,2表示步长
    print(i)

for + break

for i in range(50,101,3):  # 顾头不顾尾,2表示步长
    if i == 53:
    break  # 中断循环
print(i)

for + continue

for i in range(50,101,3):  # 顾头不顾尾,2表示步长
    if i == 53:
    continue  # 跳出本次循环，不执行下面的代码
print(i)

for + else (as understood only): for loop is not terminated break on the implementation of the code in the else, or do not perform

for i in range(50,101,3):
    if i == 1000:
    break
    print(i)
else:
    print('如果没有被break终止我就打印')

Print loading state "Loading ...."

import time

print('loading',end=' ')

for i in range(6):
    print('.',end='')
    time.sleep(0.2)    # 间隔0.2秒打印一个'.'