python 2 7 dictionary

Python note (7): dictionary, class, attribute, object instance, inheritance, python instance (1) Brief Description A dictionary is a Python built-in data structure that associates data with keys (for example, name: Zhang San, name

Python self-study day-Two day (2)-python-list-tuples-dictionary, python- ListFormat: name = []Name = [name1, name2, name3, name4, name5] # List operations Name. index ("name1") # query the name of the specified value. count ("name1") # query the name of the total number of s

‘:"Value1",‘Key2‘:{‘K1‘:‘V1‘,‘K2‘:[‘vv1 ", ' vv2 ' "}, "key3 ": 886, "key4": [ ' armin", Modifications to dictionaries and lists in nested:A_dict ={‘Key1‘:"Value1",‘Key2‘:{‘K1‘:‘V1‘,‘K2‘:[‘Vv1‘,‘Vv2‘]},‘Key3': 886,‘Key4‘:[‘Armin‘,‘Admin ", [1,2,3],{" k41 ": " v41 ' }]} A_dict[ "key4"][3][ ' n "]= "test" #向 Keys4 in the fourth element Add a key n value to test. a_dict[ "key4print (a_dict) Nested applications:A_dict =[ {"Name" :"Armin","Pwd" :"123"}, {"Name" :"Admin","Pwd" :"123

first. >>> import JSON >> > Dordereddict ([( " foo , 1), (" bar , 2), (" spam , 3), ( ' grok , 4)]) >>> Json.dumps (d) " {" foo ": 1," Bar ": 2," Spam ": 3," Grok ": 4} >>> Add: Ordereddict internally maintains a doubly linked list, which arranges the position of the keys according to the order in which they are added. The first newly added element is placed at the end of the list, and subs

A dictionary of Python Learning Notes (v) 2Often used in practical programming.Example 1:copy >> ad = {"name": "WTF", "hig": "180"}>> BD = AD>> BD{' name ': ' WTF ', ' hig ': ' 180 '}>> ID (AD)4539954352>> ID (BD)4539954352Description: An object affixed with two tags, using the assignment to achieve the so-called "fake copy."If you use Copy ()>> cd = Ad.copy ()>> CD{' name ': ' WTF ', ' hig ': ' 18

Lecture 7:lists and mutability,dictionaries,pseudocode,introduction to efficiency list and variability, dictionary, pseudo Code, efficiency Lists and mutability List and variability>>> L1 = [123]>>> L2 = L1>>> print L2[123]>>> L1[04>>> print L2[423] def F(L):l[0] =4L1 = [1,2,3]L2 = [1,2,3]L3 = L1PrintL1 = = L2F (L1)PrintL1 = = L2PrintL1PrintL2PrintL3#输出TrueFalse[4,2,3][1,2,3][4,2,3]Dictionaries dictionary3w

elements of the list x to build a dictionary, the key value is the list of each element, value is None4. Get (key) to find value based on key5. Hash_key (x) find if the dictionary contains a key value x6. Update (x) updating another dictionary with one dictionary7, Popitem () delete the last element and return8, Pop (key) delete the key value corresponding to th

字符串右对齐 and fills a new string with a space to a specified lengthA.rsplit () #去掉右边空格或换行符A.rstrip () #去掉字符串右边的空格A.strip () #去掉字符串中的空格A.split () #字符串切片The A.splitlines () #按行分隔 Returns a list that contains rows as elements, and if NUM specifies that only num rows are sliced.A.startswith () #判断是不是以参数中内容开头A.swapcase () #对字符串的大小写字母进行转换A.title () #把字符串转成标题格式A.capitalize () #把字符串首字母变为大写A.endswith () #判断字符串是否以指定字符或子字符串结尾, commonly used to determine file typesA.expandtabs () #把字符串中的 the tab sign (' \ t ')

e.g. a=[[3,789],[1,100],[1,102],[2,102],[1,106],[2,456]]; Convert to a dictionary b={1:[100,102,102],2:[102,456],3:[789]}If cast is used:1 >>> a=[[3,789],[1,100],[1,102],[2,102],[1,106],[2,456]]; 2 >>> b=dict (a)3 >>> b4 {1:106, 2:456, 3:789} 5The result obviously removes the value corresponding to the duplicate key in

One. The characteristics of the dictionary. ：(1). The Python dictionary is unordered. (and the list is orderly) we can understand the dictionary as a set of key:value such a health value pair.(2). The key of the Python

1. DictionariesKey-value pairs.1dict={"Key1":"value1",2 "Key2":"value2"3 }4 5 #add a new key/value pair6dict["Key3"] ="Value3"7 8 #Change a Key/value pair9dict["Key2"] ="NewValue"Ten One #Delete a key/value pair A deldict["Key1"] - - forKey,valueinchDict.items (): the Print("%s:%s"%(key,value)) - - if "Key2" inchdict: - Print("Find Key2")2.

}2.4update operationIn []: DOUT[73]: {' C ': 1, ' xx ': 200}In [D.update]: ({' A ': 1, ' B ': 2})In []: DOUT[75]: {' A ': 1, ' B ': 2, ' C ': 1, ' xx ': 200}The 2.5 python dictionary is a reference value , such as:In []: DOUT[76]: {' A ': 1, ' B ': 2, ' C ': 1, ' xx ': 200}I

": 1}, {"b": 1})-1>>> CMP ({"a": 2}, {"a": 1})1>>> CMP ({"a": 2}, {"a": 2,"b": 1})-1Note: When CMP compares the dictionary data, it compares the keys before comparing the values.Len>>> Len ("hello itcast")12>>> len ([1, 2, 3, 4])4> >> Len ((3,4))

Python learning-2 dictionary implementation level 3 menu, Menu = {"Jiangsu ":{'Nanjing ': ["Jiangning", 'gulou', 'liuhe '],'Nantong ': ["haimen", "Rugao", "Hai 'an"],'Suzhou ': ["Kunshan", "wuzhong district", 'changshu']},"Anhui ":{'Hefei ': ["luyang", "yaohai", "Bao he", "Shushan", "feidong county", "Feixi county", "Chaohu", "Changfeng ", "hi-tech", "binhu"],'Sh

dicvisit={}if not Dicvisit.has_key (Visitkey):# does not exist Diaset = set () Diaset.add (diagnosecontent) Dicvisit[visitkey]=diaset #print ("new===" +visitkey + "-----" +diagnosecontent) Else: # take out the corresponding element value in the dictionary, it is a set, and add the diagnostics into the originaldiaset= Dicvisit[visitkey] # For item in Originaldiaset: # Print Item originaldiaset.add (diagnosecontent)Tr

Data types for Python:int (integral type)On a 32-bit machine, the number of integers is 32 bits and the value range is -2**31~2**31-1, which is -2147483648~2147483647On a 64-bit system, the number of integers is 64 bits and the value range is -2**63~2**63-1, which is -9223372036854775808~9223372036854775807long (Long i