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Python Articles
Page 852 of 854
What are the best practices for using if statements in Python?
Here are some of the steps that you can follow to optimize a nested if...elif...else.1. Ensure that the path that'll be taken most is near the top. This ensures that not multiple conditions are needed to be checked on the most executed path.2. Similarly, sort the paths by most use and put the conditions accordingly.3. Use short-circuiting to your advantage. If you have a statement like:if heavyOperation() and lightOperation():Then consider changing it toif lightOperation() and heavyOperation():This will ensure that heavyOperation is not even executed if lightOperation is false. Same can be done with or conditions as well.4. Try flattening the ...
Read MoreHow to generate statistical graphs using Python?
Python has an amazing graph plotting library called matplotlib. It is the most popular graphing and data visualization module for Python. You can start plotting graphs using 3 lines! For example, from matplotlib import pyplot as plt # Plot to canvas plt.plot([1, 2, 3], [4, 5, 1]) #Showing what we plotted plt.show() This will create a simple graph with coordinates (1, 4), (2, 5) and (3, 1). You can Assign labels to the axes using the xlabel and ylabel functions. For example, plt.ylabel('Y axis') plt.xlabel('X axis') And also provide a title using the title ...
Read MoreWhat's the difference between lists and tuples in Python?
List and Tuple are called as sequence data types of Python. Objects of both types are comma separated collection of items not necessarily of same type. However, main difference between list and tuple is that list object is mutable whereas tuple object is immutable. Immutable object can not be modified once it is created in memory. Hence it is not possible to add, modify or remove item from tuple object. On the other hand these operations can be performed on a list.
Read MoreIs there any tool that can convert an XSD file to a Python class as JAXB does for Java?
I would recommend generateDS for converting a XSD file to a Python class . In my opinion, it is a good tool for the said purpose.It (generatS) generates the Python class with all methods (setters and getters, export to XML, import from XML). It does a good job and works very well !.
Read MoreWhat Content-type is required to write Python CGI program?
If we run simple scripts like hello.py, its output is written on the STDOUT file, i.e., screen. There is one important and extra feature available which is the first line to be printed Content-type:text/html\r\r. This line is sent back to the browser and it specifies the content type to be displayed on the browser screen.We can write advanced CGI programs using Python. This script can interact with any other external system and even exchange information with RDBMS.
Read MoreWhat are repeating character classes used in Python regular expression?
A character class followed by operators like '?', '*' or '+' are called repeating character classes.If you repeat a character class by using the '?', '*' or '+' operators, you will repeat the entire character class, and not just the character that it matched. The regex '[0-9]+' can match '579' as well as '333'. If you want to repeat the matched character, rather than the class, you will need to use backreferences. '([0- 9])\1+' will match '333' but not “579”. When applied to the string “922226”, it will match '2222' in the middle of this string. If you do not ...
Read MoreWhat is the difference between __str__ and __repr__ in Python?
The built-in functions repr() and str() respectively call object.__repr__(self) and object.__str__(self) methods. First function computes official representation of the object, while second returns informal representation of the object. Result of both functions is same for integer object. >>> x = 1 >>> repr(x) '1' >>> str(x) '1' However, it is not the case for string object. >>> x = "Hello" >>> repr(x) "'Hello'" >>> str(x) 'Hello' Return value of repr() of a string object can be evaluated by eval() function and results in valid string object. However, result of str() can not be evaluated. ...
Read MoreHow many Python classes should I put in one file?
Python code is organized in files called "modules" and groups of related modules called “packages".A module is a distinct unit that may have one or more closely-related classes. Modules need to be imported before they are read, used, maintained and extended if needed. So a module is a unit or reuse.The rule is this: a module is the unit of reuse. Everything in Python libraries and other Python applications is either a module or a package of modules.There is no limit on how many classes one can put in a file or a module. It all depends on how big ...
Read MoreHow do you compare Python objects with .NET objects?
By default, all .NET objects are reference types and their equality and hash code is determined by their memory address. Additionally, assigning a variable to an existing object just makes it point to that address in memory, so there is no costly copying occurring. It appears that this is true for python objects as well to certain extent.Properties of Python objects: All python objects havea unique identity (an integer, returned by id(x)); a type (returned by type(x))You cannot change the identity; You cannot change the type.Some objects allow you to change their content (without changing the identity or the type, that is).Some ...
Read MoreHow to compress Python objects before saving to cache?
We need sometimes to compress Python objects (list, dictionary, string, etc) before saving them to cache and decompress after reading from cache.Firstly we need to be sure we need to compress the objects. We should check if the data structures/objects are too big just to fit uncompressed in the cache. There is going to be an overhead for compression/decompression, that we have to tradeoff with the gains made by caching in the first place.If we really need compression, then we probably want to use zlib.If we are going to use zlib, we might want to experiment with the different compression ...
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