======================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：
1 sum = 0 2 start = 1 3 while start < 999999999: 4 sum = sum + start 5 print(sum) 6 start = start + 1
1-99所有数求和：
1 """ 2 print('开始了...') 3 num = 1 4 sum = 0 5 while num <= 99: 6 sum = sum + num 7 num = num + 1 8 print(sum) 9 print('end') 10 """ 11 12 print('开始了...') 13 num = 0 14 sum = 0 15 while num < 100: 16 sum = sum + num 17 num = num + 1 18 print(sum) 19 print('end')
1-99所有奇数求和：
1 """ 2 print('开始了... ') 3 num = 1 4 sum = 0 5 while num <=99: 6 result = num % 2 7 if result == 1: 8 sum = sum + num 9 num = num + 1 10 print(sum) 11 print('end') 12 13 """ 14 print('开始了... ') 15 num = 0 16 sum = 0 17 while num < 100: 18 num = num + 1 19 result = num % 2 20 if result == 1: 21 sum = sum + num 22 print(sum) 23 print('end')
打印1-99所有奇数：
1 print('开始了... ') 2 num = 0 3 while num <= 99: 4 result = num % 2 5 if result == 1: 6 print(num) 7 num = num + 1 8 print('end') 9 10 11 """ 12 print('开始了... ') 13 num = 0 14 while num <= 99: 15 num = num + 1 16 result = num % 2 17 if result == 1: 18 print(num) 19 print('end') 20 """ 21 """ 22 print('开始了... ') 23 num = 0 24 while num < 100: 25 num = num + 1 26 result = num % 2 27 if result == 1: 28 print(num) 29 print('end') 30 """
if嵌套示例：
1 name = input('请输入用户名：') 2 if name == '名锐杰': 3 age = input('请输入年龄：') 4 if age == "18": 5 print('好帅好帅') 6 else: 7 print('不帅') 8 elif name == '李泉': 9 print('好浪好浪') 10 elif name == '刘永希': 11 print('好诗好诗') 12 else: 13 print('编不下去了') 14 print('end')
模拟银行卡3次输错密码强制退出：
1 count = 1 2 while True: 3 name = input('请输入用户名：') 4 if name == "Alex": 5 print('欢迎登陆！') 6 num = input('请输入取款金额：') 7 else: 8 print('用户名输入错') 9 count = count + 1 10 if count == 4: 11 break 12 13 14 15 """ 16 count = 1 17 while count < 4: 18 name = input('请输入用户名：') 19 if name == "Alex": 20 print('欢迎登陆！') 21 num = input('请输入取款金额：') 22 else: 23 print('用户名输入错') 24 count = count + 1 25 """
字符串运算：
1 print("你好，老狗") 2 3 name = "老狗" 4 print(name) 5 6 age = 18 7 age1 = age 8 age2 = age1 9 print(age2) 10 11 12 result = 1 + 1 13 print(result) 14 result = 1 - 1 15 print(result) 16 result = 1 * 1 17 print(result) 18 result = 1 / 1 19 print(result) 20 result = "名锐杰" + "李泉" 21 print(result) 22 result = "名锐杰" * 8 23 print(result) 24 25 26 """" 27 if 条件: 28 print('真') 29 else: 30 print('假') 31 """ 32 33 name = input ('请输入用户名') 34 if name == 'alex': 35 msg = name + '是傻叉' 36 print(msg) 37 else: 38 print(name) 39 40 """ 41 简化： 42 if 条件: 43 print('真') 44 """ 45 46 """ 47 形式二： 48 if 条件： 49 print('真') 50 elif 条件: 51 print('真') 52 elif 条件: 53 print('真') 54 else: 55 print('假') 56 """ 57 58 name = input('请输入用户名') 59 if name == '名锐杰': 60 print('好帅好帅') 61 elif name == '李泉': 62 print('好浪好浪') 63 elif name == '刘永希': 64 print('好诗好诗') 65 else: 66 print('遍布下去了') 67 print('end') 68 69 70 71 name = input('请输入用户名') 72 print(name)
打印1-99中能被3整除的数字：
1 print('开始了... ') 2 num = 1 3 while num <= 99: 4 result = num % 3 5 if result == 0: 6 print(num) 7 num = num + 1 8 print('end') 9 10 """ 11 print('开始了...') 12 num = 0 13 while num < 100: 14 num = num + 1 15 result = num % 3 16 if result == 0: 17 print(num) 18 print('end') 19 """
1-99-sum-substract
1 print('开始了... ') 2 num = 0 3 sum = 0 4 sum1 = 0 5 sum2 = 0 6 while num < 99: 7 num = num + 1 8 result = num % 2 9 if result == 1: 10 sum1 = sum1 + num 11 print(sum1) 12 else: 13 sum2 = sum2 + num 14 print(sum2) 15 sum = sum1 - sum2 16 print(sum) 17 print('end')
1-99-sum-odd-num-subtract-sum-even-num
1 print('开始了... ') 2 num = 1 3 sum = 0 4 while num <=99: 5 result = num % 2 6 if result == 1: 7 sum = sum + num 8 else: 9 sum = sum - num 10 print(sum) 11 num = num + 1 12 print(sum) 13 print('end') 14 15 """ 16 print('开始了... ') 17 num = 0 18 sum = 0 19 sum1 = 0 20 sum2 = 0 21 while num < 99: 22 num = num + 1 23 result = num % 2 24 if result == 1: 25 sum1 = sum1 + num 26 # print(sum1) 27 else: 28 sum2 = sum2 + num 29 # print(sum2) 30 sum = sum1 - sum2 31 print(sum) 32 print('end') 33 """