python bokeh examples

This article mainly introduces the usage examples of Python _ setattr _, _ getattr _, _ delattr _, and _ call, this article explains these magic methods separately. For more information, see Getattr The 'getattr' function is a built-in function and can be obtained by function name. The code is as follows: Value = obj. attributeValue = getattr (obj, "attribute ") Use 'getattr 'to implement the factory mode

to use Os.path.join (Dirpath, name). Auto-complete recursive enumeration via for loop for example: F:\aaa directory is such a file directory structure f:\aaa|--------1.txt| --------2.txt|--------3.txt|--------4 |-------5.txt |-------6.txt |-------7.txt Os.walk (Top, Topdown=true, Onerror=none, Followlinks=false) can get a ternary tupple (Dirpath, Dirnames, filenames), the first one for the starting path, The second is the folder under the starting path, and the third one is the file under the s

Examples of how to add and compare the combined values of the dictionary in Python. Sum of dictionary merge valuesWhen collecting and summarizing game data, some data is stored in dictionaries every day. When I want to collect statistics for multiple days, I need to merge the dictionaries.If the keys are the same, their values are added.The update method cannot be used, because the value of the same key is

-dimensional list becomes a two-dimensional list, the two list changes at the same timeThis is a shallow copy, cloning only the first layer listThe second list is a reference to the first listBased on the shallow copy, modify the copy out of the list, you can implement the concept of similar inheritanceDeep copyImport CopyCopy.copy (a_list): shallow copy, same as A_list.copy ()Copy.deepcopy (a_list): Deep copyDon't use it. Large amount of data memory consumptionTwo-dimensional listEach element i

.insert (1, ' abc ')SortList2.sort ()ReverseList2.reverse ()Delete and return a valueList.pop (1)Append elementList2.extend (' Qweq ')Tuple ()Tuples and lists are similarTuples and strings are not becoming-tuples can store a range of values-tuples are typically used in user-defined functions to safely take a set of worthwhile times, that is, the value of the tuple being used does not change.T= (1,a,)Split of a B c=t tupleCommon methods of dictionaries> Dictionary is the only type of mapping (has

This article mainly introduces the usage examples of super in Python, this article compares the general inheritance with the super inheritance, from the results of the run, ordinary inheritance and super inheritance are the same, but in fact their internal operating mechanism is different, this point in multiple inheritance is evident, Need friends can refer to the following Super is used to solve multiple

Let's take a look at an example: Copy Code code as follows: >>> def foo (*args, **kwargs): print ' args = ', args print ' Kwargs = ', Kwargs print '-----------------------' >>> if __name__ = = ' __main__ ':Foo (1, 2, 3, 4)Foo (a=1, b=2, c=3)Foo (1,2,3,4, A=1, b=2, c=3)Foo (' A ', 1, None, a=1, b= ' 2 ', c=3) The output results are as follows: Copy Code code as follows: args = (1, 2, 3, 4) Kwargs = {} ----------------------- args = () Kwargs

Careful use of variable length parametersPython supports variable-length parameter lists, which can be implemented by *arg, **kwargs these two special syntaxes. The following examples are used for variable length parameters:* Use *args to implement the variable parameter list: *args with AcceptA parameter list wrapped as a tuple to pass a non-critical parameter, and the number of parameters can be arbitrary. def sumfun (*args): Result = 0 for

Examples and differences of using exit, return, sys. exit () in Python This article mainly introduces the use cases and differences of exit, return, sys. exit () and so on in Python. This article is a summary of a practical project. For more information, see There is a question: String identifier. modify the idcheck of Example 6-1. py script to detect the identi

. Struct. UnpackStruct. Unpack is the opposite of struct. Pack. It is used to replace byte Transfer with Python data type. Its function prototype is struct. Unpack (FMT, string). This function returns a tuples. The following is a simple example: Str = struct. Pack ("II", 20,400)A1, a2 = struct. Unpack ("II", STR)Print 'a1: ', A1Print 'a2: ', A2# ---- Result:# A1: 20# A2: 400STR = struct. Pack ("II", 20,400)A1, a2 = struct. Unpack ("II", STR)Print 'a1

, etc. Examples of how to use Env.roledefs:Env.roledefs = {' webserver ': [' 192.168.1.21 ', ' 192.168.1.22 '], ' dbserver ': [' 192.168.1.25 ', ' 192.168.1.26 ']}# A python adorner is used to refer to a grouping, such as: @roles (' webserver ') def webtask (): Run ('/usr/local/nginx/sbin/nginx ') @roles (' webserver ', ' DBServer ') def publictask (): Run (' uptime ')Fabric Common APIsLocal #执行本地命令, such a

value of the variable K, and the second%s is replaced by the value of V. All other characters of the Python format string (in this case, the equals sign) are printed out as-is. Note (k, v) is a tuple. String formatting is more than just a connection. It's not even just formatting. It is also a coercion type conversion. String Formatting vs. String joins >>> uid = "sa" >>> pwd = "secret" >>> print pwd + "is not a good password for" + UID Secret is n

Before we talked about the Python advanced data Structure Learning tutorial, let's take a look at some of the advanced Python design structures and how they are used. in daily work, you can choose the right data structure for your needs, such as requirements for fast lookup, requirements for data consistency, or requirements for indexing, and you can combine various data structures appropriately to gener

This paper describes the use of Optionparser module in Python in detail, and it has good reference value for studying python in depth. Share for everyone to use for reference. The specific analysis is as follows: In general, there are two built-in modules in Python that handle command-line arguments: One is getopt, "Deep in

This article mainly introduces examples of Python smtplib module to handle the use of e-mail, is the basics of Python introductory learning, need friends can refer to the In internet-based applications, programs often need to send e-mail automatically. For example: A website registration system will send a message to confirm registration when the user registers;

This article mainly introduces the differences between Python and C programming ideas through examples. as a representative of object-oriented and process-oriented programming languages, the comparison between the two is classic, for more information about how to use Python to process various data science projects, see. Pytho