conversionsInt ("5") # is converted to an integer integerfloat (2) # converted to a floating-point number Floatlong ("23") # converted to a long integer long Integerstr (2.3) # converted to a string Stringcomplex (3, 9) # returns complex Number 3 + 9iord ("a") # "a" character corresponds to the value Chr (65) # VALUE 65 corresponds to the character unichr (65) # VALUE 65 corresponds to the Unicode character bool (0) # converted to the corresponding true and False value, in
First article on the path to Python Development (2)-First knowledge list and metadata, the path to python Development
The list and element groups can be treated as normal "arrays", which can store any number of Python objects of any type. Like arrays, the
number of the floor except//is always an integer, even if not endless. To do the exact division, use/can. Because//division takes only the integer part of the result, Python also provides a remainder operation that can get the remainder of two integers:>>> 10 31 Regardless of whether the integer is a//division or the remainder, the result is always an integer, so the result of the integer operation is always accurate.
formatting strings
#!/usr/b
', ' DD ') delete element value by subscript13. Sort the values in the list using the sort () method (only the list of pure numbers, pure letters) can be sortedlist= [' DD ', ' cc ', ' BB ', ' AA ']List.sort () #[' aa ', ' BB ', ' cc ', ' DD ' default ascending orderList.sort (reverse=true) #[' DD ', ' cc ', ' BB ', ' AA ']List.sort (reverse=false) #[' aa ', ' BB '
Advanced functions of list in python, pythonlist list
In all the data structures of Python, list is very important and convenient. This article mainly describes the advanced application of list. You can view the blog with basic kn
I want to learn more about Python, know more about list, and know more about list.
List Parsing
Let's take a look at the following example. In this example, we want to get the square of each integer from 1 to 9 and put the result in the list to print it out.
>>> power2 = []>
' Age=28Addr='Chengdu' Money='200w'Cars='1w Units'words='INSERT INTO user values ("%s", "%s", "%s", "%s", "%s", "%s");'% (User,sex,age,addr,money,cars)#order can not be chaotic, must be in order toPrint(words)The output is:Insert into user values ("Emily", "female", "28", "Chengdu", "200w", "1w Station")Mode 2user ='Emily'Sex='female' Age=28Addr='Chengdu' Money='200w'Cars='1w Units'SQL='INSERT into user values ({name},{sex},{age},{addr},{qian},{che})'New_sql=sql.format (age=age,che=cars,name=use
']
Eight, pop
#Original list>>>name_list['Root','GM','Test','HLR','Root']#remove a value with a list position of 2>>> Name_list.pop (2)'Test'#New List>>>name_list['Root','GM','HLR','Root']#Delete the last value of a list>>>Name_list.pop ()'Root'#New List>>>name_li
By using the List Builder, you can quickly generate a list that can derive another list from a list, while the code is very concise.format [x for x in content][x for x in content if condition]1: To put the generated element x in front, execution, the first to execute the later for loop2: You can have multiple for loops
List generation: Creating a listFirst, the normal creation list#!/usr/bin/python#common EstablishLis1 = [];For x in range (1, 10):Lis1.append (x);Print "Lis1:", lis1;Ii. List-Generated#List comprehensionsLIS2 = [x for x in range (1, 10)]Print "Lis2:", Lis2;#also can choose t
Python Data Structure linked list: one-way linked list (instance description)
Unidirectional linked list
A one-way linked list is also called a single-chain table. It is the simplest form of a linked list. Each node contains two f
, has side effects, so there should be no return value.
2. In terms of legibility, Guido van Rossum
The Python-dev mailing list also explains why the return value of X.sort () is chosen to be None. (Original message: [Python-dev] Sort () return value
)
3. From a performance and usability standpoint, the Python Doc ex
Python Create Listone of the data types built into Python is the list: lists. A list is an ordered set of elements that can be added and removed at any time.For example, by listing the names of all the classmates in the class, you can use a list to indicate:>>> [' Michael ',
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
This article mainly introduces three methods of traversal (sequence number and value) in the Python List (List) to traverse the sequence number and value in the List:
I recently learned the python language and felt that it has greatly improved my work efficiency. I wrote
Use of the List. insert () method in the Python operation List
This article mainly introduces the use of the List. insert () method in the Python operation List. It is the basic knowledge in the
This article describes how to create a list in python and assign an initial value to the list. It involves Python list definition and assignment techniques, for more information about how to create a list using
Python for loop clever use (iteration, list generation), python generationIntroductionWe can use the for loop to iterate the list, tuple, dict, set, and string. dict is not sequential in storage, so iteration (traversal) the order of the output values also changes. Iteration
Python List (List) Three traversal (sequence number and value) methods, pythonlist
Three methods are used to traverse the serial numbers and values in the list:
I recently learned the python language and felt that it has greatly improved my work efficiency. I wrote this blog
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