Python 基础知识教程

了解python基本语法 尝试写简单的python程序

 1 count = 0 2 age_to_guess = 23 3  4 while count<3: 5     age_guessed = int(input("age:")) 6     if age_guessed == age_to_guess: 7         print("congratulations") 8         break 9     elif age_guessed > age_to_guess:10         print("Too big")11     else:12         print("Too small")13     count = count + 114     if count == 3:15         confirm_input = input("Do you want to play more?")16         if confirm_input != "n":17             count = 0

1 age_to_guess = 232 age_guessed = int(input("age:"))3 4 if age_guessed == age_to_guess :5     print("Congratulations")6 elif age_guessed > age_to_guess:7     print("Too big")8 else:9     print("Too small")

 1 import sys 2  3 ''' 4 print(sys.path) #打印环境变量 5 print(sys.argv) #相对路径 可在后面加参数 6 ''' 7  8 #操作系统模块 9 import os10 11 cmd_result = os.system("dir") #执行命令 不保存结果12 print(cmd_result) #输出0 为什么? os.system是直接在频幕上输出 没返回13 14 cmd_result_internal_storage = os.popen("dir") #打开的是一个内存地址15 print(cmd_result_internal_storage)16 cmd_result_content = os.popen("dir").read() #读操作17 print(cmd_result_content)18 19 os.mkdir("new_dir") #创建目录20 21 msg = "我爱北京*"22 23 msg_bytes= msg.encode("utf-8")24 25 print(msg_bytes)26 27 msg_str = msg_bytes.decode("utf-8")28 29 print(msg_str)

python list 用法(增删改查):

   names = [, , , ,    (names[2 (names[1:3])  (names[2 (names[:-1 (names[-3:-1])    names.append()    names.insert(2,    names.insert(4,     names[2] =     names.remove(   names[3  names.pop()     (names.index( (names[names.index( (names.count( names.reverse()   names.sort()   names2 = [1, 2, 3, 4         (names)
执行结果:

 1 D:\python\python\python.exe D:/xampp/htdocs/python/day2/list_cut.py 2 num1 3 num3 4 ['num2', 'num3'] 5 ['num3', 'num4', 'num3'] 6 ['num1', 'num2', 'num3', 'num4'] 7 ['num3', 'num4'] 8 ['num1', 'num2', 'num3', 'num4', 'num3', 'num10086'] 9 ['num1', 'num2', 'num_', 'num3', 'num4', 'num3', 'num10086']10 ['num1', 'num2', 'num_', 'num3', '_num', 'num4', 'num3', 'num10086']11 ['num1', 'num2', 'change2', 'num3', '_num', 'num4', 'num3', 'num10086']12 ['num1', 'num2', 'num3', '_num', 'num4', 'num3', 'num10086']13 ['num1', 'num2', 'num3', 'num4', 'num3', 'num10086']14 ['num1', 'num2', 'num3', 'num4', 'num3']15 216 num317 218 ['num3', 'num4', 'num3', 'num2', 'num1']19 ['num1', 'num2', 'num3', 'num3', 'num4']20 ['num1', 'num2', 'num3', 'num3', 'num4', 1, 2, 3, 4]21 []22 23 进程已结束,退出代码0

python list 用法(复制 循环):

 1 #author F 2 import copy 3  4  5 #copy 列表浅复制 6  7 names = ["name1", "name2", "name3", ["alibaba", "blili"], "name4", "name5"] 8 names2 = names.copy() #浅copy:只copy第一层地址 原因:复制的第二层列表的指针地址 9 print(names)10 print(names2)11 12 names[1] = "name_change"13 # print(names)14 # print(names2)15 16 names[3][1] = "BLILI"17 print(names)18 print(names2)19 20 '''21 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']22 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']23 ['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']24 ['name1', 'name2', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']25 '''26 27 # = 列表复制28 names = ["name1", "name2", "name3", ["alibaba", "blili"], "name4", "name5"]29 names2 = names30 print(names)31 print(names2)32 33 names[1] = "name_change"34 # print(names)35 # print(names2)36 37 names[3][1] = "BLILI"38 print(names)39 print(names2)40 '''41 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']42 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']43 ['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']44 ['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']45 '''46 47 #  模块复制48 names = ["name1", "name2", "name3", ["alibaba", "blili"], "name4", "name5"]49 names2 = copy.deepcopy(names) #深copy : 会占用两份独立的内存空间 慎用50 print(names)51 print(names2)52 53 names[1] = "name_change"54 # print(names)55 # print(names2)56 57 names[3][1] = "BLILI"58 print(names)59 print(names2)60 '''61 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']62 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']63 ['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']64 ['name1', 'name2', 'name3', ['alibaba', 'blili'], 'name4', 'name5']65 '''66 67 #循环68 for i in names:69     print(i)70 71 print(names[0:-1:1])  #['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4']72 print(names[0::1])  #['name1', 'name_change', 'name3', ['alibaba', 'BLILI'], 'name4', 'name5']

元组 浅copy补充

 1 person = ["name", ["saving", 123]] 2 #浅copy的三种实现方式 3 ''' 4 p1 = copy.copy(person) 5 p2 = person[:] 6 p3 = list(person) 7 ''' 8 p1 = person[:] 9 p2 = person[:]10 11 p1[0] = 'ale1'12 p2[0] = 'feng'13 14 p1[1][1] = 5015 16 print(p1) #联合账号的用法17 18 #元组19 names = ('231', ' 21314')20 # 元组只有index和count方法

 1 what_he_does = ' plays ' 2 his_instrument = 'guitar' 3 his_name = 'Robert Jhonson' 4 artist_intro = his_name + what_he_does + his_instrument 5  6 print(artist_intro) 7 print(type(what_he_does)) 8  9 10 num = 111 string = '1'12 print(num+int(string))13 14 word = 'word'15 words = word*316 print(words)17 18 word = 'word'19 num = 120 astr = word * (len(word) - num)21 print(astr)22 23 word = 'friends'24 find_the_evil_in_your_friends = \25 word[0] + word[2:4] + word[-3:-1]26 print(find_the_evil_in_your_friends)27 28 tel = '135-8866-9555'29 hide_tel = tel.replace(tel[:9], '*'*9)30 print(hide_tel)31 32 search = '234'33 num_a = '135-8855-2345'34 num_b = '123-2346-2346'35 print(search + ' is at ' + str(num_a.find(search)) + ' to ' + str(num_a.find(search)+len(search)) + ' of num_a')36 print(search + ' is at ' + str(num_b.find(search)) + ' to ' + str(num_b.find(search)+len(search)) + ' of num_b')37 38 39 print('{} a word she can get what she {} for.'.format('With', 'came'))40 print('{prepositon} a word she can get what she {verb} for.'.format(prepositon='With', verb='came'))41 print('{0} a word she can get what she {1} for.'.format('With', 'came'))42 43 # city = input("write down the name of city:")44 # url = "http://api.baidu.com/wather?city={}".format(city)45 # print(url)46 47 48 def f_c(c):49     f = c*9/5 + 3250     return str(f) + '°F'51 52 fahrenheit = f_c(35)53 print(fahrenheit)

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