======================学习python==================
介绍:
python种类:
cpython(*),jpython,ironpython,rubypython,pypy ...
种类有很多,规则只有一个

python版本
Python2.7
Python3.x

学习Phtyon,学习规则
1. 安装解释器
python.exe 解释器程序

2. 写代码,让解释器运行
”黑框“:开始->cmd->回车

- 解释器路径 代码文件路径 (写代码)

添加操作系统环境变量:C:\Python35;

python 代码文件路径
- 解释器 (简单功能测试)

3. python2.7和python3.5共存,推荐:C,D:

规则:
1. print("你好,老狗")
py2(accii): 中文报错
py3(utf-8):不报错

老外开发计算机,只能识别:
- accii码(255个东西),字母,数字,符号...
- utf-8编码,包含世间万物
代码头部写上(-python pytho官方推荐方法):
#-*- encoding:utf-8 -*-

2. 变量
a、基础
变量名 = 值

print("老狗")

name = "老狗"
print(name)

PS:
变量名要求:
- 可有:字母,数字,下划线
- 数字不能开头
- 不能是Python内部关键字:[ 'and','as' ...]

- 建议:见名知意

b、小高级
age = 18
age1 = age
age2 = age1
print(age2)

3.初识数据类型
age = 18 整数类型
name = "名锐杰" 字符串类型
gender = True/False 布尔类型

#比较运算
result = 19 > 18
result = 19 < 18
result 19 >= 18
result 19 == 18

#数值运算
result = 1 + 1
result = 1 - 1
result = 1 * 1
result = 1 / 1
result = "名锐杰" + "李泉" # "名锐杰李泉"
result = "名锐杰" * 8 # "名锐杰名锐杰名锐杰名锐杰名锐杰名锐杰名锐杰名锐杰"

4. 条件语句
如果:条件,
- 成立:xxxx
- 不成立:xxxx

形式一:
if 条件:
print('真')
else:
print('假')

示例:
name = input('请输入用户名')
if name == 'alex':
msg = name + '我是傻叉'
print(msg)
else:
print(name)

简化:
if 条件:
print('真')

形式二:
if 条件:
print('真')
elif 条件:
print('真')
elif 条件:
print('真')
else:
print('假')

示例:
name = input('请输入用户名')
if name == '名锐捷':
print('好帅好帅')
elif name == '李泉':
print('好浪好浪')
elif name == '刘永希':
print('好诗好诗')
else:
print('编不下去了')

示例:
name = input('请输入用户名')
if name == '名锐捷':
print('好帅好帅')
elif name == '李泉':
print('好浪好浪')
elif name == '刘永希':
print('好诗好诗')
else:
print('编不下去了')
print('end')

变形:
示例(嵌套):
name = input('请输入用户名')
if name == '名锐捷':

age = input('请输入年龄:')
if age == "18":
print('好帅好帅')
else:
print('不帅')
elif name == '李泉':
print('好浪好浪')
elif name == '刘永希':
print('好诗好诗')
else:
print('编不下去了')
print('end')

5. 输入
name = input('请输入用户名') # 让用户输入内容,输入内容赋值给name变量
print(name)

python3 输入方法:
name = input('>>>')
python2 输入方法:
name = raw_input('>>>')

PS: 输入的内容------永远是字符串类型

6. 循环

while语句特征:

场景一:
while 条件:
条件成立,执行此处代码(执行完毕,再回到条件处)

print(1)
if True:
print(2)
print(3)
---------不会循环

print(1)
while True:
print(2)
print(3)
--------永远打印2----死循环

print(1)
while True:
print(2)
print(22)
print(32)
print(3)

print(1)
flag = True
while flag:
print(2)
flag = False
print(3)

print(1)
start = 0
flag = True
while flag:
print(start)
flag = False
print(3)

print(1)
start = 0
flag = True
while flag:
print(start)
start = start + 1
print(3)

场景二:
while 条件:
条件成立,执行此处代码(执行完毕后,再回到条件)
else:
条件不成立,

示例:
#输出: 1-100连续数字
start = 1
flag = True
while True:
print(start)
start = start + 1
if start == 100:
flag = False

print('开始...')
start = 1
flag = True
while True:
print(start)
start = start + 1
if start == 100:
print(start)
flag = False
print('结束了...')

print('开始...')
start = 1
while start < 101:
print(start)
start = start + 1
print('结束了...')

#################################
补充两个关键字: continue,break
#################################

break----跳出当前循环的外面,执行外面的代码

print(0)
while True:
print(1)
break # 跳出当前循环
print(11)
print(2)

continue------跳,跳到True的位置,继续下一次循环(下面示例中的prin11,永远不会执行)

print(0)
while True:
print(1)
continue # 结束本次循环,进行下次循环
print(11)
print(2)

使用break实现:1-100

start = 1
while True:
print(start)
start = start + 1
if start == 100
print(start)
break

输出: 1 2 3 4 5 6 8 9 10

start = 1
while start < 11:
if start == 7:
print(' ')
else:
print(start)
start = start + 1

start = 1
while start < 11:
if start == 7:
pass
else:
print(start)
start = start + 1

start = 1
while start < 11:
if start == 7:
start = start + 1
continue
else:
print(start)
start = start + 1

while循环总结:
1. 书写规则
while 条件:
成立执行...
else:
不成立执行

2. continue,break

赠送:
1. 奇偶数
num = 19
result = num % 2
if result == 0:
print('偶数')
else:
print('奇数')

2. 1-100总和

sum = 0
start = 1
while start < 101
sum = sum + start
print(sum)
start = start + 1

练习题:
1. 打印 1-99之间所有的奇数
print('开始了... ')
num = 0
while num < 100:
num = num + 1
result = num % 2
if result == 1:
print(num)
print('end')

"""
print('开始了... ')
num = 0
while num <= 99:
num = num + 1
result = num % 2
if result == 1:
print(num)
print('end')
"""
"""
print('开始了... ')
num = 0
while num <= 99:
result = num % 2
if result == 1:
print(num)
num = num + 1
print('end')
"""

2. 打印1-99之间所有能被3整除的数
print('开始了...')
num = 0
while num < 100:
num = num + 1
result = num % 3
if result == 0:
print(num)
print('end')

print('开始了... ')
num = 1
while num <= 99:
result = num % 3
if result == 0:
print(num)
num = num + 1
print('end')

3. 打印1-99之间所有数的总和
"""
print('开始了...')
num = 1
sum = 0
while num <= 99:
sum = sum + num
num = num + 1
print(sum)
print('end')
"""

print('开始了...')
num = 0
sum = 0
while num < 100:
sum = sum + num
num = num + 1
print(sum)
print('end')

4. 打印1-99之间所有奇数的总和
print('开始了... ')
num = 0
sum = 0
while num < 100:
num = num + 1
result = num % 2
if result == 1:
sum = sum + num
print(sum)
print('end')

print('开始了... ')
num = 1
sum = 0
while num <=99:
result = num % 2
if result == 1:
sum = sum + num
num = num + 1
print(sum)
print('end')

5. 1-2+3-4+5-6+7...+99 之间所有数总和
print('开始了... ')
num = 0
sum = 0
sum1 = 0
sum2 = 0
while num < 99:
num = num + 1
result = num % 2
if result == 1:
sum1 = sum1 + num
# print(sum1)
else:
sum2 = sum2 + num
# print(sum2)
sum = sum1 - sum2
print(sum)
print('end')

print('开始了... ')
num = 1
sum = 0
while num <=99:
result = num % 2
if result == 1:
sum = sum + num
else:
sum = sum - num
num = num + 1
print(sum)
print('end')

print('开始了... ')
num = 1
sum = 0
while num <=99:
result = num % 2
if result == 1:
sum = sum + num
else:
sum = sum - num
print(sum)
num = num + 1
print(sum)
print('end')

>>> dir(list)
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
>>>

>>> dir(__builtins__)
['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning', 'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError', 'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning', 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False', 'FileExistsError', 'FileNotFoundError', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError', 'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'NameError', 'None', 'NotADirectoryError', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError', 'RecursionError', 'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning', 'StopAsyncIteration', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError', 'TimeoutError', 'True', 'TypeError', 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'WindowsError', 'ZeroDivisionError', '_', '__build_class__', '__debug__', '__doc__', '__import__', '__loader__', '__name__', '__package__', '__spec__', 'abs', 'all', 'any', 'ascii', 'bin', 'bool', 'bytearray', 'bytes', 'callable', 'chr', 'classmethod', 'compile', 'complex', 'copyright', 'credits', 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'exec', 'exit', 'filter', 'float', 'format', 'frozenset', 'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex', 'id', 'input', 'int', 'isinstance', 'issubclass', 'iter', 'len', 'license', 'list', 'locals', 'map', 'max', 'memoryview', 'min', 'next', 'object', 'oct', 'open', 'ord', 'pow', 'print', 'property', 'quit', 'range', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'vars', 'zip']
>>>

通过help查看BIF的相关帮助
>>> help(input)
Help on built-in function input in module builtins:

input(prompt=None, /)
Read a string from standard input. The trailing newline is stripped.

The prompt string, if given, is printed to standard output without a
trailing newline before reading input.

If the user hits EOF (*nix: Ctrl-D, Windows: Ctrl-Z+Return), raise EOFError.
On *nix systems, readline is used if available.

>>>

while 循环脚本:

 sum = 0
start = 1
while start < 999999999:
sum = sum + start
print(sum)
start = start + 1

1-99所有数求和:

 """
print('开始了...')
num = 1
sum = 0
while num <= 99:
sum = sum + num
num = num + 1
print(sum)
print('end')
""" print('开始了...')
num = 0
sum = 0
while num < 100:
sum = sum + num
num = num + 1
print(sum)
print('end')

1-99所有奇数求和:

 """
print('开始了... ')
num = 1
sum = 0
while num <=99:
result = num % 2
if result == 1:
sum = sum + num
num = num + 1
print(sum)
print('end') """
print('开始了... ')
num = 0
sum = 0
while num < 100:
num = num + 1
result = num % 2
if result == 1:
sum = sum + num
print(sum)
print('end')

打印1-99所有奇数:

 print('开始了... ')
num = 0
while num <= 99:
result = num % 2
if result == 1:
print(num)
num = num + 1
print('end') """
print('开始了... ')
num = 0
while num <= 99:
num = num + 1
result = num % 2
if result == 1:
print(num)
print('end')
"""
"""
print('开始了... ')
num = 0
while num < 100:
num = num + 1
result = num % 2
if result == 1:
print(num)
print('end')
"""

if嵌套示例:

 name = input('请输入用户名:')
if name == '名锐杰':
age = input('请输入年龄:')
if age == "":
print('好帅好帅')
else:
print('不帅')
elif name == '李泉':
print('好浪好浪')
elif name == '刘永希':
print('好诗好诗')
else:
print('编不下去了')
print('end')

模拟银行卡3次输错密码强制退出:

 count = 1
while True:
name = input('请输入用户名:')
if name == "Alex":
print('欢迎登陆!')
num = input('请输入取款金额:')
else:
print('用户名输入错')
count = count + 1
if count == 4:
break """
count = 1
while count < 4:
name = input('请输入用户名:')
if name == "Alex":
print('欢迎登陆!')
num = input('请输入取款金额:')
else:
print('用户名输入错')
count = count + 1
"""

字符串运算:

 print("你好,老狗")

 name = "老狗"
print(name) age = 18
age1 = age
age2 = age1
print(age2) result = 1 + 1
print(result)
result = 1 - 1
print(result)
result = 1 * 1
print(result)
result = 1 / 1
print(result)
result = "名锐杰" + "李泉"
print(result)
result = "名锐杰" * 8
print(result) """"
if 条件:
print('真')
else:
print('假')
""" name = input ('请输入用户名')
if name == 'alex':
msg = name + '是傻叉'
print(msg)
else:
print(name) """
简化:
if 条件:
print('真')
""" """
形式二:
if 条件:
print('真')
elif 条件:
print('真')
elif 条件:
print('真')
else:
print('假')
""" name = input('请输入用户名')
if name == '名锐杰':
print('好帅好帅')
elif name == '李泉':
print('好浪好浪')
elif name == '刘永希':
print('好诗好诗')
else:
print('遍布下去了')
print('end') name = input('请输入用户名')
print(name)

打印1-99中能被3整除的数字:

 print('开始了... ')
num = 1
while num <= 99:
result = num % 3
if result == 0:
print(num)
num = num + 1
print('end') """
print('开始了...')
num = 0
while num < 100:
num = num + 1
result = num % 3
if result == 0:
print(num)
print('end')
"""

1-99-sum-substract

 print('开始了... ')
num = 0
sum = 0
sum1 = 0
sum2 = 0
while num < 99:
num = num + 1
result = num % 2
if result == 1:
sum1 = sum1 + num
print(sum1)
else:
sum2 = sum2 + num
print(sum2)
sum = sum1 - sum2
print(sum)
print('end')

1-99-sum-odd-num-subtract-sum-even-num

 print('开始了... ')
num = 1
sum = 0
while num <=99:
result = num % 2
if result == 1:
sum = sum + num
else:
sum = sum - num
print(sum)
num = num + 1
print(sum)
print('end') """
print('开始了... ')
num = 0
sum = 0
sum1 = 0
sum2 = 0
while num < 99:
num = num + 1
result = num % 2
if result == 1:
sum1 = sum1 + num
# print(sum1)
else:
sum2 = sum2 + num
# print(sum2)
sum = sum1 - sum2
print(sum)
print('end')
"""

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