Python basic knowledge list, Ganso, dictionary/String.

A list of basic knowledge:

The list is defined by [] and can be appended and deleted by querying the index values.

Common usage is as follows

names = [' Zhang ', ' Zhuang ', [' Alx ', ' Bob '], ' Chen ', ' Qiang ']print (len (names))  # Gets the list length print ("Aaffaa". Count ("a"))  # Get a number of occurrences of a string print (Names[1:3])  # Slice print (names[-1])  # get the last element print (names[-2:])  #  Names.append (' qianqq ') #追加模式names. Insert (1, ' Chengrouhua ')  # inserting Names.insert (3, "Xinzhiyu") names[2] = "IXNIXN"  # Modify Names.remove ("Qiang") # del names[0]# names.pop (0)  Delete element and return the value of the deleted element del Names[2:4]  # Slice Delete for i in names:< C10/>print (i)  # Loop through the list for I in range (1, 2):    print (i)   #每隔2位数打印print (Names[::2])  # interlace filter Print (' Zhuang ' in names) #判断字段是否在列表里names2 = Names.copy () #浅浅的copyprint (dir (names))  #获取列表所支持的方法 # #分割 # s = ' Hello World ' # S.S Plit (') # [' Hello ', ' World ']# s2= ' Hello,world ' # s2.split (', ') # # #连接 # l = [' Hi ', ' Eva ']# '! '. Join (L) # ' Hi!eva '

　

2. Yuan Zu, is a kind of not become a list form, once the definition can not be changed, generally used for database connection, binding IP and port use.

Ganso Features:

1. Immutable, when defining the ancestor if there is only one element that must be distinguished by commas after ganso. Note: The meta-ancestor can be modified if there are mutable elements such as lists

2. Only query function. Querying internal data through indexed values.

3. Dictionaries: defined in the form of {k1:v1} in key:value form to create, is a mutable data type

Dictionaries can be added and modified by the following methods:

info={#         ' stu1101 ': "Wu  teng  lang", #         ' stu1102 ': "Cang", #         ' stu1103 ': "Xiaoze", #         ' stu1104 ': " Bo Jie "#         }# # b={1:2,3:4}# # # # print (info[' stu1101 '])   #查看字典stu1101 key corresponding to value# # info[' stu1101 ']= ' mmmmm '   # If the dictionary has this key value then modify, no then add # # info[' stu1105 ']= ' sssss ' # # Info.setdefault (' stu1101 ', ' alxe ')   #如果key的值 in the dictionary is modified, no then add # # Info.update (b) # Appends the field of the B dictionary to the info dictionary, if repeated updates are followed by fields. # # Print (info) # # Info.pop (' stu1105 ')  #通过key的值来删除字典的对应的值 pop method has a return value that returns the value of the deleted element # # # # # print (Info.get (' stu1106 ') # This is a way to get the value through the key so it won't be an error, no then return none# # Print (' stu1104 '  in info)  #判断key的值在不在字典中 to be judged by key values. # # Print (Info.keys ()) #返回所有的key  #打印所有字典key的 Value # # print (Info.values ()) #返回字典所有的value值 # # Print (Info.items ()) # Return to the Yuan Zu c15/> the key with the value of the meta-ancestor #  #   for K in info:# K is the key   of info traversal dictionary key value Printing # # Print     (K,info[k])

Set: The whole of one or more elements is called a set.

Features of the collection:

1. Natural weight

2. The inner elements of the collection are unordered

3. By operation you can take out two sets of eligible element types to form a new set

The common set operations are as follows:

b={1,2,3,4,5,5,5,6}  #互异性天然去重的原则 # c={2,3,4,8,9,10,56,45}# info={#     ' stu1101 ': "Wu  teng  lang", #     ' stu1102 ': "Cang", #     ' stu1103 ': "Xiaoze", #     ' stu1104 ': "Bo Jie" #     }# # #print (b-c)  # The idea is to take each element of B minus the elements in C and get a different set. # # Print (b|c)  #并集两个集合的合并 # # print (b^c)  #两个集合中不是共同部分的元素取出来 # # D=set (info)  #设置集合  Dictionary is the value of key # # print (d # B.add (  #增加元素 # b.remove) #删除元素 If there is no element then error # # B.discard (4) #删除元素  no error # # print (b) # # # # B.pop ()  #删除元素 (any) # # print (b)

Some of the operating postures of characters are as follows

# name= ' aaalcx lill ' # Print (Name.index ("L")) # Print (Name.count ("L")) # Statistic string number of a string # print (Name.capitalize ()) #首字母大写 # Print (Name.center, ' * ')) #把name放在中间 50 characters # print (Name.replace (' l ', ' l ', 4)) #代替 three parameter # print ("123". IsDigit ()) #判断是否是整数 # print ("Aaaooolll". EndsWith (' ll ')) # msg = "My name is {}, and the age is {}" # Print (Msg.partition (' is ')) #is in the middle of the meta-ancestor # print (msg . Format ("ZJ", "+") # Name.join ("CX") # Print (Name.join ("Cxb") # to manipulate numbers "' Name= ' abcd Lill ' name1=" ABC \tlill "#  Name.strip () #变成字符串 # name.title () #变成标题 # Print (Name.rsplit ()) print (Name.capitalize ()) #首字母大写print (Name.count ("a")) # Statistical character print (Name.center ("*")) #一共 print 50 characters not enough to fill, put name in middle print (Name.endswith ("ll")) # to determine the end of the string print (Name1.expandtabs (30)) Print (Name.find ("Li")) # Find Index! The string can be sliced name3= "My name is {name} and the age was {age}" print (Name3.format (name= "Alix", age= ")" Print (Name3.format_map ({" Name ":" Alex "," Age ":"} ") Print (Name3.index (" y ")) print (Name.isalnum ()) # is not the Arabic numerals print (Name.isalpha ()) # Judge the Pure English character print (Name.isdecimal ()) #判断十进制print (name.isDigit ()) # Determines if the integer print (Name.isidentifier ()) #判断是不是合法的标识符 (variable name) print (Name.islower ()) # is lowercase! Print (Name.isnumeric ()) #判断是否是数字!! Just the number returned Trueprint (Name.isspace ()) print (Name.istitle ()) print (Name.isprintable ()) # is printable! The TTY file device terminal file Print (Name.isupper ()) # is all uppercase print ("* * * *") print ("|"). Join (["1", "2", "3", "4"]) # The string inside the list becomes the string print ("* * * *") print (Name.ljust (50, "-")) # after the top *print (name.rjust (50, '-')) Print (Name.lower ()) # Uppercase becomes lowercase print (name.upper ()) print ("\nalex\n". Lstrip ()) #左边去空格或者回车print ("\nalex\n". Rstrip ()) # Go to the right side of the space or enter print (Name.strip ()) #两边都去空格print ("Funny keys\n") V=str.maketrans ("ABCdef", "123456") # number corresponding! Print ("Alex Li". Translate (v)) print ("Alex L". Replace (' l ', ' l ', 1)) print ("Alex Li". RFind ("L")) #找到最右边的的l and return to print ( Name.split ()) # The photo space is divided into the list print (Name.split (' A ')) # Photo A divided into list print (Name.splitlines ()) # According to line break Linux Windowprint (NAME.S Tartswith (' a ')) print (Name.swapcase ()) #大小写转换print (Name.title ()) # variable title print ("Alex Li". Zfill (50)) # 50 not enough in front of 0 "" Print ("Name AAA". Split ()) name= ' AA aaaa ' Print (Name.isaLpha ()) # Judging is not the letter! Print (len (' Hello '. Encode ()))

　　

Python basic knowledge list, Ganso, dictionary/String.