python dictionary of dictionaries

Python dictionary key-Value Pair addition and traversal methods, python dictionary Add a key-Value Pair First define an empty dictionary >>> Dic = {} Directly assign values to keys that do not exist in the dictionary. >>> dic['nam

can writePerson_info.keys ()#Show only KeyPerson_info.setdefault ('Gentle','male')#Set the default value, there is no change, no joinNew_info= {' Age': 19,'Addr': ['Wuhan','Beijing']}person_info.update (new_info)#Update the new dictionary to the old dictionaryPrintperson_info['name']#print is used in the file to outputPrintPerson_info.items ()#items default to the index and value (in the form of a list)PrintPerson_infoNote: The following are two type

Common Methods for operating the dictionary type in python (recommended) and for operating the dictionary type in python The has_key () method can check whether the dictionary contains the specified key. If yes, True is returned. Otherwise, False is returned. Syntax format:

fromCollectionsImportdefaultdictImportJSONdeftree ():returndefaultdict (tree) Categories=tree () a= categories['Programming Languages']['Python']b= categories['Programming Languages']['Java']a['Standard Library']['SYS']='SYS'a['Standard Library']['OS']='OS'b['Standard Library']['OS']='Jos'Print(Json.dumps (categories)) output: {"Programming Languages": {"Python": {"Standard Library": {"SYS":"SYS","OS":"OS"}

In the Python manual:Sorted (Iterable[,cmp,[,key[,reverse=true]])Function: Return a new sorted list from the items in iterable.The first parameter is a iterable, and the return value is a list that sorts the elements in iterable. The optional parameters are three, CMP, key, and reverse. 1) CMP Specifies a custom comparison function that receives two parameters (elements of iterable), returns a negative number if the first argument is less than the sec

parentheses, of course, curly braces is a dictionary.★ There are 2 small details, first:If the list is only 1 digits, then it's OK, but tuple is using parentheses, in order for Python to know that you are here to define a tuple of 1 elements, a= (1,): A=[x. >>> A=[1] >>> a [1] >>> a= (1) >>> A A it's a number, not a tuple. >>> a= (1,) >>> a (1,) >>> Second small detail: the invariant of a tuple refers to

'){1: ' t ', 2: ' t ', 3: ' t '}Update () #将两个字典的内容进行整合, if the consolidated dictionary key exists in the consolidated key during the integration process, replace the original value to ensure that there are no duplicate keys in the dictionaryScan two-dimensional code, Changbai Mountain Souvenir650) this.width=650; "Src=" https://s1.51cto.com/wyfs02/M01/8D/E4/wKioL1iuilSRyP1mAAH4lkqQ0cE404.png-wh_500x0-wm_ 3-wmp_4-s_2600682946.png "title=" qq picture

2-1 How to filter data in lists, dictionaries, and collections based on criteria Preliminary knowledge:In this section we will use the Randint,lambda,timeit,filter and other keywordsThe usual practice is to iterate through the current list and then place the element in the list that satisfies the condition in another listFrom random import RandintRandint (A,B) return random the integer in range [A, b], including both end points. use of the Timeit func

("abcdef", "123456")Print ("Alex Li". Translate (p))Replacement string: A_str.replace (' l ', ' l ', 1)Find character position in string from right to left: A_str.rfind (' x ')Separates a string into a list by a specified character, without specifying a space: A_str.split ()Separate strings by carriage return as a list: A_str.splitlines () (\r,\n?). ）Case conversion: A_str.swapcase ()Fill in 0 of the string with insufficient parts: A_str.zfill (50)Dictionary7.18,7.19,7.21,7.28,8.28,2.28Key-valu

':'Jones','UID': 1003}, {'fname':'David','lname':'Beazley','UID': 1002}, {'fname':'John','lname':'Cleese','UID': 1001}]sorted by uid:[{'fname':'John','lname':'Cleese','UID': 1001}, {'fname':'David','lname':'Beazley','UID': 1002}, {'fname':'Brian','lname':'Jones','UID': 1003}, {'fname':'Big','lname':'Jones','UID': 1004}]sorted by lname,fname:[{'fname':'David','lname':'Beazley','UID': 1002}, {'fname':'John','lname':'Cleese','UID': 1001}, {'fname':'Big','lname':'Jones','UID': 1004}, {'fname':'Brian

parameter list according to function F. For example:>>> L = [1,2,3,4,5]>>> map (lambda x:x*x, L)[1,4,9,16,25]The reduce (f, list) function is similar to map, whose argument f function receives two parameters, and all elements in the returned list are the result of the cumulative calculation of all elements in the parameter list according to function f, such as additive/multiplicative:>>> L = [1,2,3,4,5]>>> reduce (lambda x,y:x+y, l)15>>> reduce ( Lambda x,y:x*y, l)120Then using these two functi

引, can also not be specified, do not specify from the bottom to start deletingDel Name_list[i]Effect: spare tire and punctureHReverse () #列表反转Sort () #排序Remove ()Iv. GansoAOnly count () and index () are supportedFive, dictionaryAFavorite_languages = {' Jane ': ' Python ',' Jack ': ' C + + ',' Rose ': ' PHP ',' Jaymes ': ' Java ',}For I in Favorite_languages:Print (i)#默认输出keyBKey: Favorite_languages.keys ()Value: Favorite_languages.values ()Kv:favorite

Basic python Tutorial Study Notes --- (4) dictionary and python Study NotesSequence is a data structure in python, and ing is another. Mapping refers to a value by name. The only ing structure built in python is a dictionary. The

Today a friend gives a demand: Come on. {' IsOK ': 1, ' isrunning ': None, ' IsError ': none} How to convert into a dictionary Well, one look is that JSON conversion is simple and begins: Live out not to result, also reported wrong, check two hours of Baidu, did not understand. Finally, the direct copy of the online code, OK, run successfully, but put my a variable, no, error; Start comparing two variables what is different, always thought

Today a friend gives a demand:Come to {' IsOK ': 1, ' isrunning ': None, ' IsError ': none} How to convert into a dictionary Well, the first thing to see is that JSON transformation is simple: Import JSON a = "{' IsOK ': 1, ' isrunning ': None, ' IsError ': none}" print Json.loads (a) Anyway out of the results, also reported wrong, check for two hours of Baidu, did not understand. Finally, copy the code directly from the Web, OK, run s

Python combines dictionary key values and removes duplicate elements. python dictionary Suppose there is a dictionary in python as follows: X = {'A': '1, 2,3 ',' B ': '2, 3,4 '} To merge: X = {'C': '1, 2, 3, 4 '} Three things need

The list in 1.python is not able to traverse delete1 #Python list We are not able to traverse delete2Li = [1, 2, 3, 4, 5, 6]3 forIinchRange (len (LI)):4 Print(i)5 delLi[i]6 Print(LI)7 #Output Result:8 #Traceback (most recent):9 #0Ten #[2, 3, 4, 5, 6] One #File "C:/users/xzb/pycharmprojects/s1/day7/python considerations. Py", line 5, A #1 - #del Li[i