Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Python Articles
Page 800 of 855
Measure execution time of small Python code snippets (timeit)
The Timer class and other convenience functions in timeit module of Python's standard library are designed to provide a mechanism to measure time taken by small bits of Python code to execute. The module has a command line interface and the functions can be called from within program as well.Easiest way to measure time of execution is by using following convenience functiontimeit()This function returns object of Timer class. It mainly requires two parameters.stmt − a string containing valid Python statement whose execution time is to be measured.setup − a string containing Python statement which will be executed once, primarily to ...
Read MorePython Utilities for with-statement contexts (contextlib)
contextlib module of Python's standard library defines ContextManager class whose object properly manages the resources within a program. Python has with keyword that works with context managers. The file object (which is returned by the built-in open() function) supports ContextManager API. Hence we often find with keyword used while working with files.Following code block opens a file and writes some data in it. After the operation is over, the file is closed, failing which file descriptor is likely to leak leading to file corruption.f = open("file.txt", "w") f.write("hello world") f.close()However same file operation is done using file's context manager capability ...
Read MoreTop-level script environment in Python (__main__)
A module object is characterized by various attributes. Attribute names are prefixed and post-fixed by double underscore __. The most important attribute of module is __name__. When Python is running as a top level executable code, i.e. when read from standard input, a script, or from an interactive prompt the __name__ attribute is set to '__main__'.>>> __name__ '__main__'From within a script also, we find a value of __name__ attribute is set to '__main__'. Execute the following script.'module docstring' print ('name of module:', __name__)Outputname of module: __main__However, for an imported module this attribute is set to name of the Python script. ...
Read MoreBuilt-in objects in Python (builtins)
The builtins module is automatically loaded every time Python interpreter starts, either as a top level execution environment or as interactive session. The Object class, which happens to be the base class for all Python objects, is defined in this module. All built-in data type classes such as numbers, string, list etc are defined in this module. The BaseException class, as well as all built-in exceptions, are also defined in it. Further, all built-in functions are also defined in the built-ins module.Since this module is imported in the current session automatically, normally it is not imported explicitly. All the built-in ...
Read MoreAccessing The Unix/Linux password database (pwd)
The pwd module in standard library of Python provides access to the password database of user accounts in a Unix/Linux operating system. Entries in this Password database are atored as a tuple-like object. The structure of tuple is according to following passwd structure pwd.h file in CPython APIIndexAttributeMeaning0pw_nameLogin name1pw_passwdOptional encrypted password2pw_uidNumerical user ID3pw_gidNumerical group ID4pw_gecosUser name or comment field5pw_dirUser home directory6pw_shellUser command interpreterThe pwd module defines the following functions −>>> import pwd >>> dir(pwd) ['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'getpwall', 'getpwnam', 'getpwuid', 'struct_passwd']getpwnam() − This function returns record in the password database corresponding to the specified user name>>> pwd.getpwnam('root') pwd.struct_passwd(pw_name ...
Read MoreDisassembler for Python bytecode
The dis module in Python standard library provides various functions useful for analysis of Python bytecode by disassembling it into a human-readable form. This helps to perform optimizations. Bytecode is a version-specific implementation detail of the interpreter.dis() functionThe function dis() generates disassembled representation of any Python code source i.e. module, class, method, function, or code object.>>> def hello(): print ("hello world") >>> import dis >>> dis.dis(hello) 2 0 LOAD_GLOBAL 0 (print) 3 LOAD_CONST 1 ('hello world') 6 CALL_FUNCTION 1 (1 positional, 0 keyword pair) 9 POP_TOP 10 LOAD_CONST 0 (None) 13 RETURN_VALUEBytecode ...
Read MoreSynchronization and Pooling of processes in Python
Synchronization between processesMultiprocessing is a package which supports spawning processes using an API. This package is used for both local and remote concurrencies. Using this module, programmer can use multiple processors on a given machine. It runs on Windows and UNIX os.All equivalent synchronization primitives are present in this package.Example codefrom multiprocessing import Process, Lock def my_function(x, y): x.acquire() print ('hello world', y) x.release() if __name__ == '__main__': lock = Lock() for num in range(10): Process(target= my_function, args=(lock, num)).start()Here one instance can lock ...
Read MoreMultiprocessing In Python
The multiprocessing package supports spawning processes. It refers to a function that loads and executes a new child processes. For the child to terminate or to continue executing concurrent computing, then the current process hasto wait using an API, which is similar to threading module.IntroductionWhen we work with Multiprocessing, at first we create process object. Then it calls a start() method.Example codefrom multiprocessing import Process def display(): print ('Hi !! I am Python') if __name__ == '__main__': p = Process(target=display) p.start() p.join()In this example, ...
Read MoreScraping and Finding Ordered Word in a Dictionary in Python
For solving this problem we need requests module.For installing requests module, we need this command to get executed at command line.pip install requestsScrapingImport requests module.Then we need to fetch data from URL.Using UTF-8 decode the text.Then convert string into a list of words.Ordered FindingTraverse the list of words using loop.Then compare the ASCII value of adjacent character of each word.If the comparison is true then print ordered word otherwise store the unordered word.Example codeimport requests def Words_find(): my_url = ""#put thisurl of .txt files in any website my_fetchData = requests.get(my_url) ...
Read MorePage Rank Algorithm and Implementation using Python
The PageRank algorithm is applicable in web pages. Web page is a directed graph, we know that the two components of Directed graphsare -nodes and connections. The pages are nodes and hyperlinks are the connections, the connection between two nodes.We can find out the importance of each page by the PageRank and it is accurate. The value of the PageRank is the probability will be between 0 and 1.The PageRank value of individual node in a graph depends on the PageRank value of all the nodes which connect to it and those nodes are cyclically connected to the nodes whose ...
Read More