Section Seventh: Python lists, tuples, dictionaries, collections

Python personal note, purely convenient query: ############################################################################################ ######### #i =[' car ', ' clothes ', ' ipone ']       #语法i            #查看所有的元素i [0]      #取第一个i [1]     # Take a second i[-1]     #取最后一个  i[0:10]    #取一个到第九个  i[-5:]        #取最后五个  i[:5]        #取前五个   i.append          #i. Append (' Darren ')     #往i追加一个元素. i.count             #i. Count (' Darren ')         #统计darren的数量. i.extend           #i. Extent (range )   # Mister into a list, and then add in the I list. I.index (559)     #查找第一个559的位置.  i[ i.index (559)  ]    #先找到559 This is worth subscript, then look for 559.     i.insert         according to subscript     #i. Insert (3, ' IBM ')    insert ibm i.remove       in 3rd element    #i. Remove (' IBM ')    delete an IBM value. i.sort               #排序   (first digit, Re-letter) i.pop               #删掉最后一个元素. i.reverse         #倒序把所有的IBM改成HP: For n in range (I.count ( ' IBM '):         #取几次  i[i.index (' IBM ')]= ' HP '---------------------- ---------------------------import stringstring.ascii_letters            #列出a-Z case string.ascii_lowercase    #列出a-Z lowercase A-Z into the list: A.split ()                 #把a-Z The entire string becomes a list. List (a)                  # Turn A-Z every string into a list str (a)                    #把列表里的多个字符串拼接成一个字符串, this is not a good place to turn a list into a string, there are special uses, described below. Type (a)                #查看a是列表还是字符串 '. Join (a)               #把列表a的每个元素以空拼接起来, into a string. '-'. Join (a)              #以-The string in a is spliced together.   type (str (4))         #把数字类型int变成字符串string, The number is converted to a string because it is not allowed to write int to the file when it is written.     f.writelines (a)    #  writes the list to the file. del a[6:11]        # Delete list 6-10 rows-------------------------------python tuples---------------------------------  tuple features: Non-modifiable, non-writable, read only.  tuple (a)          #把一个列表变成元组. List (d)             #把一个元组变成列表. --------------------------------------------------------------------------------a.isdigit ()       #判断是否为数字, is true, otherwise falsea.isalpha ()    #判断是否为字符串, or True, otherwise falsesys.exit (' goodbye! ')      # Normal exit-------------------------python dictionary------------------------a key corresponding to a value:dictname ={          "Key1"  :  "value1",         " Key2 " : " value2 "}-------------------------------------------------------the key corresponds to a list: contacts ={          "Darren"     :    [' man ', ' it ', ' 15621008081 '],         ' Wang '        :    [' man ', ' engineer ', ' &nbsp ';]}------------------------------print  Contacts[' WANg ']             #打印出字典contact中key为wang的列表. contacts[' Wang '][1]= ' Kings '     #把字典中key为wang的列表种, element 1 changed to kingsprint contacts[' Wang ']            contacts[' Wang ']=[' woman ', ' Linux ', ']  '       #把key对应的列表下所有的值都改变        contacts.has_key (' Wang ')            #查看是否有wang这个key. Contacts.items ()            #列出字典, becomes a list, and then columns each key below each list has a tuple. -----------------------------------For x,y contacts.items ():               #把字典里的内容, print out each line. X is the value corresponding to the Key,y key.     print x,y------------------------------------for i in contacts:                       #把字典里的内容打印出, similar to the way it was. Print i,contact[i]a.get (' sex ')             #获取一个key, If there is a value, no error will be entered. A.keys ()                 # Print only Keya.pop (' age ')           #删除一个keya [' Sex '] = ' mans '         #添加一个key对应的值 overrides the value if the key already exists. A.setdefault (' haha ', ' it ')            #添加一个key和值, such as haha have no change in data, If not, add it. A.update (b)            #把b字典里的数据, fused into A's dictionary. A.values ()               #不重要, mainly to look at the proportion of data in a unified state. A.copy ()                 #  b=a.copy ()      b copies the contents of a. A.clear ()              #清空Dictionary adel  a                       #删除字典a     help  (b.values ())    # View the usage of the help. A= ' Stu110a.find (' s ')       #查找a中是否有s, some words list element position, no words for -1################################# #################### #query =raw_input (' pelase input your query: ') for k,v in test_ Dict.items ():          #查看字典的key和values                    index = k.find ( Query)                # Find out if there are elements in the key that the user wants to query, and then assign the element subscript to indexprint k[:index] +  ' \033[32;1m%s\033[0m '  % query  + k[index + len (query):],v                 #                match_ counter +=1               #match自增1  key=key[:index]+query+key[index+len (Qury):]k = [a b c d e f]k[:2]     #列表中取0元素到 ' two values ' k[2:]    #列表中取第2个元素到最后值例子: import stringfor i in  string.lowercase:    print string.lowercase.index (i)      Print i----------------------------------for i,v in enumerate (string.lowercase):     print i,v           #x效果和上面一样, is the function of enumerations, Let the obtained value have subscript.  ------------------------dictionaries are unordered and cannot be sorted, now use a parameter to sort the dictionaries. A={4: ' B ', 2: ' A ', 9: ' 2 ', 8: ' d '}a.items ()        #把字典变成一个列表, below the list is a tuple. [(8,  ' d '),  (9,  ' 2 '),  (2,  ' a '),  (4,  ' B ')]sorted (A.items (), key=lambda x:x[0])     #把元组赋给lambda, lamdba the first element of a list. The most important feature of-------------------------Python collection------------------------collection is the weight, but not the subscript. A=[1,2,3,4,5,6,7,8,9]b=[1,2,3,4,11]set (a)          #把列表a变成集合set (b)           #把列表b变成集合a  & b           #交集, A and B have values a | b           #求合集, A and B have all been combined, but will be removed from the repetition. A -a.difference (b)           #a中有的, b.difference not in B (a)            #b中有的, a-b         not in a #在a中, not b-a         #在b中 in B, not in a a ^ b       #把a和b不共有的列出来a. Add (' x ')          #添加一个数值, if any, is not added, A.update ([ 10,11,12])          #添加一个列表len (a)                #查看集合的长度50  in a              #测试50是否在a中, when True is returned, Falsea.issubset (b)           #测试是否b中的每一个元素都在a中a  >=ba<=b                         #测试是否a中的每一个元素都在b中. Hash (' s ')                    #返回s的hash值拉链zip: A=[1,2,3,4,5]b=[6,7,8,9,10]zip (A, b)         # Combine two lists [(1, 6),  (2, 7),  (3, 8),  (4, 9),  (5, 10)]map (None,  b)              #如果不对称则显示为none [(1, 6),  ( 2, 7),  (3, 8),  (4, 9),  (5, 10),  (0, none)]&NBSP;&NBSP;&NBSP;&NBSP;-------------------------python iterator------------------------f.next ()          #一次只读一行, read it down until you have an error. Interable

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Section Seventh: Python lists, tuples, dictionaries, collections