Class notes: Python Basics-dictionaries

Two main features of the Python Dictionary: unordered, key unique

#字典创建
dic={'name':'Alex'}#The first form ofDic2=dict (('name','Alex'),))#The second form ofPrint(dic2) dic3=dict ([['name','Alex'],])#The third form ofPrint(DIC3)#dic1={' name ': ' Alex '}#dic1[' age ']=18#print (DIC1)#key exists, does not change, returns the value corresponding to the corresponding key in the dictionary#ret=dic1.setdefault (' age ',)#print (ret)###键不存在, add a new key-value pair in the dictionary and return the corresponding value#ret2=dic1.setdefault (' Hobby ', ' girl ')#print (DIC1)#print (Ret2)#Search through the keys to find#dic3={' age ': ' Name ': ' Alex ', ' hobby ': ' Girl '}##print (dic3[' name '])##Print (List (Dic3.keys ())) #输出所有键#Print (List (dic3.values ())) #输出所有键值#Print (List (Dic3.items ())) #输出所有键值#Dictionary Modification#li=[1,2,34,4]#li[2]=5#dic3={' age ': ' Name ': ' Alex ', ' hobby ': ' Girl '}#dic3[' age ']=55#print (DIC3)#dic4={' age ': ' Name ': ' Alex ', ' hobby ': ' Girl '}## dic5={' 1 ': ' 111 ', ' 2 ': ' 222 '}#dic5={' 1 ': ' 111 ', ' name ': ' 222 '}##dic4.update (DIC5)#print (DIC4)#print (DIC5)#dic5 = {' name ': ' Alex ', ' age ': +, ' class ': 1}#dic5.clear () # Empty the dictionary#print (DIC5)#del dic5[' name '] #删除字典中指定键值对#print (DIC5)#Print (Dic5.pop (' age ')) #删除字典中指定键值对 and returns the value of the key-value pair#ret=dic5.pop (' age ')#print (ret)#print (DIC5)#a = Dic5.popitem () #随机删除某组键值对, and returns the value in tuple form#print (A, dic5)#del dic5 #删除整个字典#print (DIC5)#5 Other operations and the methods involved#Dic6=dict.fromkeys ([' host1 ', ' host2 ', ' host3 '], ' test ')#print (dic6) #{' host3 ': ' Test ', ' host1 ': ' Test ', ' host2 ': ' Test '}##dic6[' host2 ']= ' abc '#print (DIC6)#Dic6=dict.fromkeys ([' host1 ', ' host2 ', ' host3 '],[' test1 ', ' tets2 '])#print (dic6) #{' host2 ': [' test1 ', ' tets2 '], ' host3 ': [' test1 ', ' tets2 '], ' host1 ': [' test1 ', ' tets2 ']}##dic6[' host2 '][1]= ' test3 '#print (dic6) #{' host3 ': [' test1 ', ' test3 '], ' host2 ': [' test1 ', ' test3 '], ' host1 ': [' test1 ', ' Test3 ']}#Av_catalog = {#"Europe and America": {#"www.youporn.com": ["a lot of free, the world's largest", "General quality"],#"www.pornhub.com": ["a lot of free, also very big", "quality than Yourporn High"],#"letmedothistoyou.com": ["mostly selfie, high-quality pictures many", "resources are not many, update slow"],#"x-art.com": ["high quality, really high", "all charges, Dick than please bypass"]#     },#"Japan and Korea": {#"Tokyo-hot": ["How the quality is not clear, the individual has not liked the Japanese and Korean fan", "Heard is charged"]#     },#"Continent": {#"1024": ["All free, really good, good Life Peace", "server in foreign countries, slow"]#     }# }#av_catalog[' Europe and America '] ["www.youporn.com"][1]= ' high-definition afternoon horse 'DiC={5:'555', 2:'666', 4:'444'}#Dic.has_keys (5)#print (5 in dic)#print (sorted (Dic.items ()))#dic5={' name ': ' Alex ', ' age ':#For i in DIC5:#print (I,dic5[i]) +#For i,v in Dic5.items ():#print (i,v)#String Manipulation#a= "Let ' s Go"#print (a)#1 * Repeating output string#print (' Hello ' *20)#2 [], [:] Get the character in the string by index, here and the list of slice operation is the same, the concrete content see list#print (' HelloWorld ' [2:])#keyword in#print (123 in [23,45,123])#print (' e2l ' in ' Hello ')#4% format string#print (' Alex is a good teacher ')#print ('%s is a good teacher '% ' Alex ')#5#a= ' 123 '#b= ' abc '#d= ' "## # c=a+b## # Print (c)# ##c= '. Join ([a,b,d])#print (c)#built-in methods for strings#st= ' Hello Kitty {name} is {age} '##Print (St.count (' L ')) # Number of statistics elements#print (St.capitalize ()) # Capitalize first letter#Print (St.center (50, ' # ')) # Center#Print (St.endswith (' Tty3 ')) # to determine whether to end with a certain content#Print (St.startswith (' he ')) # to determine whether to start with a content#Print (St.expandtabs (tabsize=20))#Print (St.find (' t ')) # finds the first element and returns the index value#Print (St.format (name= ' Alex ', age=37)) # Another way to format the output is to be determined:?: {}#print ({' Name ': ' Alex ', ' Age ': St.format_map} )#Print (St.index (' t '))#print (' ASD '. Isalnum ())#print (' 12632178 '. Isdecimal ())#print (' 1269999.uuuu '. IsNumeric ())#print (' abc '. isidentifier ())#print (' ABC '. Islower ())#print (' ABC '. Isupper ())#print (' E '. isspace ())#print (' My title '. Istitle ())#print (' My tltle '. Lower ())#print (' My tltle '. Upper ())#print (' My tltle '. Swapcase ())#print (' My tltle '. Ljust (+, ' * '))#print (' My tltle '. Rjust (+, ' * '))#print (' \tmy tltle\n '. Strip ())#print (' \tmy tltle\n '. Lstrip ())#print (' \tmy tltle\n '. Rstrip ())#print (' OK ')#print (' My title title '. Replace (' itle ', ' lesson ', 1))#print (' My title title '. RFind (' t '))#print (' My title title '. Split (' I ', 1))#print (' My title title '. Title ())#pick some important string methods#1 Print (St.count (' l '))#Print (St.center (50, ' # ')) # Center#Print (St.startswith (' he ')) # to determine whether to start with a content#Print (St.find (' t '))#Print (St.format (name= ' Alex ', age=37)) # Another way to format the output is to be determined:?: {}#print (' My tltle '. Lower ())#print (' My tltle '. Upper ())#print (' \tmy tltle\n '. Strip ())#print (' My title title '. Replace (' itle ', ' lesson ', 1))#print (' My title title '. Split (' I ', 1))

Class notes: Python Basics-dictionaries