> For the complete documentation index, see [llms.txt](https://twinsant.gitbook.io/untitled-1/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://twinsant.gitbook.io/untitled-1/006.while-xun-huan.md).
# 006.while循环
山无陵，江水为竭，冬雷震震，夏雨雪， 天地合，乃敢与君绝！
《上邪》是我国汉代一首著名的乐府诗歌，它是一个痴情的女子对爱情的忠贞表白。
## 复习逻辑条件
这节课需要同学们先复习not和and
{% hint style="info" %}
问题：not True的值是什么？False and True的值是什么？
回答：请在脑子里运行这两个逻辑表达式，不熟的请看上节课的教程来复习
{% endhint %}
## 折行
有这样一个程序
```python
# 程序006.01
cond1 = True
cond2 = True
cond3 = True
cond4 = True
cond5 = True
cond6 = True
if cond1 and cond2 and cond3 and cond4 and cond5:
print('Bam!')
```
if有5个条件，如果编辑器显示不下我们会想把条件折行输入，这样写会出错
```python
# 程序006.02
cond1 = True
cond2 = True
cond3 = True
cond4 = True
cond5 = True
cond6 = True
if cond1 and cond2 and cond3 and cond4
and cond5:
print('Bam!')
```
因为Python的代码块逻辑被打断了
要想折行，只需要在代码行最后加上\，告诉Python下一行续写这一行的代码
```python
# 程序006.03
cond1 = True
cond2 = True
cond3 = True
cond4 = True
cond5 = True
cond6 = True
if cond1 and cond2 and cond3 and cond4 \
and cond5: # 这样写等价于程序006.01
print('Bam!')
```
## 整数变量
前面我们介绍了字符串变量，现在我们再介绍下整数变量
```python
i = 1 # 我是一个整数变量
```
顾名思义，整数变量就是存放整数的容器，在这个变量上，我们可以做各种算数操作
```python
# 程序006.04
i = 1
print(i) # 打印1
i = i + 1 # 还有一个简化写法是 i += 1
print(i) # 打印2
i = i - 1 # 还有一个简化写法是 i -= 1
print(i) # 打印1
print(i < 2) # 打印True
```
让我们把这首情诗改成完整的Python程序
```python
# 程序006.05
mountain_without_peaks = False
river_runs_dry = False
winter_thunder_rolls = False
summer_rain_turns_to_snow = False
heaven_earth_merged = False
life = 18
while not mountain_without_peaks and not river_runs_dry and not winter_thunder_rolls\
and not summer_rain_turns_to_snow and not heaven_earth_merged and life < 100:
print(f'{life} years old: I love you!')
life += 1
print('I love you forever...')
```
课后作业
{% hint style="info" %}
问题： 修改for循环为while循环
```python
for i in range(10, 0, -1):
print(i)
```
{% endhint %}
