Python隨筆(一)、python基礎
在pycharm下設置自己的模板:
在File---settings---File and Code Templates---Python script 腳本裏添加:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:${USER}
@file: ${NAME}.py
@time: ${YEAR}/${MONTH}/${DAY}
"""
一、第一個python程序:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:Administrator
@file: HelloWorld.py
@time: 2017/11/{DAY}
"""
print("HelloWorld!!!")
print("你好,世界")
二、變量和賦值:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:Administrator
@file: bianliang.py
@time: 2017/11/18
"""
#賦值
name = "chenjisong"
age = 30
print(name,age)
字符串類型的必須要加引號
a = 3
b = a
a = 5
print(a,b)
返回結果為(5,3)
解析:a = 3,內存地址指向3,b = a,則b = 3,此時a 和 b 都指向內存地址3,當 a = 5的時候,a 的內存地址指向了5,則a = 3 這個內存地址被回收了,但是b的內存地址未被回收,b仍然等於3,所以最後返回的結果是(5,3)
變量起名的原則:
1、顯示,通俗易懂
2、駝峰寫法(首字母大寫) 例如:NumsOfJackGf
3、下橫線寫法(不能為中橫線) 例如:nums_of_jack_gf
4、不能數字開頭,但是可以在中間和結尾
5、命名中不能有特殊字符
6、變量的命名不能有空格
7、關鍵字不能聲明為變量
內存地址的驗證:
C:\Users\Administrator>python
Python 3.6.3 (v3.6.3:2c5fed8, Oct 3 2017, 18:11:49) [MSC v.1900 64 bit (AMD64)]
on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import keyword
>>> a = 5
>>> b = a
>>> id(a),id(b)
(1363763552, 1363763552)
a 和 b的內存地址完全一樣
>>> a = 10
>>> id(a),id(b)
>>> (1363763712, 1363763552)
當a的值改變之後,a的內存地址也發生了變化(是python中的內存地址,不是物理機器的內存地址)
三、用戶交互
[root@python3 ~]# python
Python 3.6.3 (default, Nov 12 2017, 04:07:16)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> name = input("please input your name:")
please input your name:chenjisong
>>> print(name)
chenjisong
>>> a = 5
>>> eval(‘a‘)
5
四、條件判斷與縮進
IF....ELSE和縮進
偽代碼:
如果 你是富二代
我們倆就拍拖
或者 你很努力上進
我們可以接觸試試
否則
免談
縮進要一致:
sex = input ("plsase input your gender:")
if sex == "gril":
print("I would like to have a baby")
elif sex == "man":
print("going to homesexual!")
else:
print("Pervert!!!")
遊戲:猜幸運數字:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:Administrator
@file: lucky_number.py
@time: 2017/11/18
"""
lucky_number = 18
guess_number = int(input("can you guess my lucky_number:"))
if guess_number > lucky_number:
print("guess_number is bigger then lucky_number")
elif guess_number < lucky_number:
print("guess_number is smaller then lucky_number:")
else:
print("congratulations,you guess it,but no prize")
五、循環控制:
break結束循環:(猜對即跳出循環,沒猜對就一直猜)
while True:
lucky_number = 18
guess_number = int(input("can you guess my lucky_number:"))
if guess_number > lucky_number:
print("guess_number is bigger then lucky_number")
elif guess_number < lucky_number:
print("guess_number is smaller then lucky_number:")
else:
print("congratulations,you guess it,but no prize")
break
while lucky_number != input_num:
input_num = int(input("input the guess num:"))
if input_num > lucky_number:
print("the real number is smaller")
elif input_num < lucky_number:
print("the real number is bigger")
else:
print("bingo")
六、循環次數限制:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:Administrator
@file: lucky_number.py
@time: 2017/11/18
"""
lucky_number = 18
input_num=-1
guess_count = 0
#while lucky_number != input_num:
while guess_count < 3:
input_num = int(input("input the guess num:"))
print("guess count:",guess_count)
if input_num > lucky_number:
print("the real number is smaller")
elif input_num < lucky_number:
print("the real number is bigger")
else:
print("Bingo!")
break
guess_count += 1
else:
print("try too many times")
兩重判斷:
第一重:三次猜不對直接退出(guess_count>3),打印“try too many times”
第二重:猜對了直接打印bingo,退出
for循環猜數字遊戲:
#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:Administrator
@file: lucky_number.py
@time: 2017/11/18
"""
#while True:
lucky_number = 18
input_num=-1
for i in range(5):
input_num = int(input("input the guess num:"))
if input_num > lucky_number:
print("the real number is smaller")
elif input_num < lucky_number:
print("the real number is bigger")
else:
print("Bingo!")
break
else:
print("try too many times")
七、常用數據類型
數據類型:
數字:
int(整型)
float(浮點型)
long(長整型)
布爾:(True(1) 和 False(0)) 真和假
字符串 str
列表 list
元祖 tuple
字典 dict
type可以查看數據類型:
>>> type(2**10)
<class ‘int‘>
>>> type(2.99)
<class ‘float‘>
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Python隨筆(一)、python基礎