Strings concatenation and Formatting in Python

Strings concatenation and Formatting in Python is the process for joining small string to make the bigger. For example, you can create a full name by joining two string like Firstname and Lastname. Formatting will help to display variable in or end of the string.

Strings Concatenation in Python

Python provides the easy way to concatenate Strings by using + (plus)  and * (star) Sign. There are other methods such as append(), join() and format().

Using + 

+ will adds values on either side of the operator

Here is an example :

Using *

*  Creates new strings, concatenating multiple copies of the same string.

Here is an example :

String Formatting in Python

You might have the experience to use C language to print String and Integer using %s and %d. Python has similar string formatting to create new, formatted strings. The % operator is used to format variables.

Here are the examples:

String formatting using two and more than values using the tuple. A tuple is a sequence of immutable Python objects. Tuples use parentheses.

Python is supporting other function like append and join to manipulate String data.

Python Interpreter : The Best Language Interpreter

Python language is written by Guido van Rossum in late 1980 is one of the Best interpreted languages. Python is used as the first programming choice of both Google, Ubuntu, RedHat. Python Interpreter is the best interpreter.

The Python interpreter

The Python interpreter is a program that reads Python program statements and executes them immediately. To use interpreter it requires opening the command prompt or terminal windows in your development environment and write command python, and it will show this result and start interpreter. I am using Window 10’s Ubuntu shell.

Python interpreter executes program statements immediately. To Experiment python statements , Python command will start interactive mode and it will be very useful to try out things.

Here are some Examples of one-line commands:

In above examples, one will print Hello World, other will do multiplication and the third one calculates Decimal to Binary using bin().

The >>> prompt is used to enter one-line commands or code blocks that define classes or functions . In above example, only one-liner commands are given. In next example please find multi-line code blocks.

Here are some Examples of multi-line code block:

In above example, it will compare two strings.

help() function is another awesome way to get help on python keywords, functions, etc.

Here is the example of checking syntax and guide of bin command. Press q to return to python interactive interpreter.

I love the way Python Interactive Interpreter works. How about you?

 

10 Python Tips and Tricks for Beginner and 9th is interesting

Today Python is one of the most popular languages for coding in Unix/Linux world. You can find it everywhere from Web development to Server Component development, XML parsing to configuration management. Here I will be mentioning 10 Python tips and tricks for developers.

Python is pre-installed in many Operating Systems which released in last two year. Ubuntu, Redhat, Mac OS, Free BSD , Solaris, etc.

To check which version of python is installed go to shell and type:

$ python

This command will give you the version information of Python and start Python’s interactive interpreter.

Here are the few famous applications which are built using Python such as :

  • Youtube
  • OpenStak
  • Dropbox
  • Instagram

Here are 10 Python tips and tricks for Beginners and Experts.

1. Use Python Development Environment

By using Development Environment or IDE it will increase your productivity and easy to resolve error and warning. It will also help to debug the code, easy to navigate , integrate source control such as SVN, Git.

These are the recommended IDEs for Python Development.

  • PyDev – It’s free and Open Source Eclipse-based IDE . http://www.pydev.org/
  • IDLE : The Python built-in IDE, with auto-completion, helps to Format , Run and Debug python code.
  • Other commercial versions are PyCharm, WingIDE.

2. Calculate days between Today and Date.

datetime module is used to find the days between two dates. this example will find the days between today and 1 Jan 2017.

3.Command line arguments while running Python Scripts

run this script:

$ python commandlinetest.py 10 20 30

Output
No of arguments passed: 3
List of argumenrs : ['commandlinetest.py', '10', '20', '30']

sys module will have the information about arguments passed by accessing sys.argv variable. sys.argv is a list of strings representing the arguments on the command-line.

4. String Searching made easy

First Method will check if a string contains another string by using the in syntax. in takes two arguments, first on the left and second on the right, and returns True if the left argument is contained within the right argument.

Second Method offers a Library method called find(). This method is used with String Variable and it returns the position of the index of desired string. If the string is not found then -1 is returned.

5. Generating Random Numbers

Python is having the random library for generating random numbers. By default random library uses system time to generate random numbers.

Output :
Random number:-> 9
Random Range Between 10 to 20:-> 13
Random with Floating values:-> 5.012076169955613

random.randrange(10) sets the limit from 0 to 10 and return numbers between 0 to 10.

random.randrange(10,20) gives random values between 10 to 20.

random.uniform gives the result with floating value.

6. Opening WebBrowser from Python Script

webbrowser module provides the easy way to open system’s default browser with URL mention in open method.

7. Calculate Program Execution time

Many applications require a very precise time measurement. For this purpose, Python provides methods in time module. These methods will help you to measure execution time taken by the block of code.

In Linux and Unix, this command can let us know the execution of the python program.

$ time python nameofprogram.py

8. Converting the List to a String for Print

To combine any list of strings into a single string, use the join method of a string object. First print statement will join string with ” , ” and second will add new line.

Output:
one, two, three
one
two
three

9. Strings Concatenating using ” + ” and more.

Python uses + and * from manipulating String.

Using +

Using *

10. Sorting Array of String

Output:
five
four
one
three
two

Let me know your views and best Python tips in comment below.

Validate JSON using Python

Python has built-in JSON module to work with JSON data. Python is getting popular and becoming the first choice of startup development. JSON is used widely because it easy to understand, compact and built in support in JavaScript.

Validating JSON Using Python.

json.loads() method is used to validate JSON data.

Here is the function which will validate JSON data.

json.loads()

json.loads() loads the JSON data to parse, it will return true or it will fail and raised the exception. This function will work as EAFP (Easier to ask for forgiveness than permission). EAFP is python’s ideology to handle this kind of situation.

Here is the Example of Validating JSON data using Python.

These ready-made tools can be used to validate JSON data online JSON Validator on CodeBeautify. and Json Validator.

Validate JSON String Using PHP

JSON is the popular data format to transfer data between client and server. There are many JSON validators are available online such as JSON Validator and JSON Validator on CodeBeautify to validate JSON.

As a programmer, I am curious to know how these tools are working. Here I am going to explain.

json_decode() is the function which is been introduce in PHP 5.3 to validate JSON String.

About json_decode

Here is the description is given in PHP specification.

mixed json_decode ( string [, bool = false [, int = 512 [, int = 0 ]]] )

This function takes a JSON encoded the string and converts it into a PHP variable.

Here is the function which works as JSON Validator.

Let’s see how does this work.

if (!empty($data))

This condition will check the $data variable is not empty. If $data is empty, then it will return false.

@json_decode($data)

json_decode parses the data and return the PHP variable if the string is valid. If the string is not valid it will generate the error. Character “@” will suppress the error.

return (json_last_error() === JSON_ERROR_NONE);

This will check if $data is valid JSON string by comparing with JSON_ERROR_NONE. json_last_error() return the last error when json_decode() has called if there are any.

Here is the Example of Validating JSON data

All about AJAX – From Beginners to Experts – Part 1

Brief History of Web Development

Let’s go 18 years back 1996, We have just started to create web pages, static with text, static with images and wowed the world. The browser was in demand to display web pages which render HTML. Later on using Perl or C dynamic content has started to serve to a browser. As HTML and Browser evolved, Web becoming interesting, to stream video, playing games, online chatting, pay the bills, find a date and lots of other fun/work activity.

Flash Player was the key part in 2000 to the 2010 year. By using it, Advertiser has started creating animated ads and born of Rich Internet Application. With the use of Adobe Flex technology and instantly became famous. But Flash Player is not supported by Apple on Mobile devices and HTML 5 seems promising.

HTML 5 has gain popularity and started to use as to make Richer Internet Application using JavaScript and it’s framework introduced by many giants. i.e JQuery, DOJO, Backbone, Sencha , Angular.

New Trend came and that’s Single Page Application without refreshing the page, render dynamic data like Gmail does. To get data, Browser needs to send the request to the server using JavaScript and that’s called AJAX.

Brief History of AJAX

Microsoft has introduced Internet Explorer to beat Netscape Navigator and got succeed. IE become the world famous browser and introduced many functionalities like ActiveX and Iframe to load asynchronous data. In 1998 IE introduce XMLHTTP for outlook web app. Another browser like Mozilla, Safari has introduced XMLHttpRequest and IE has supported in IE 7.

JavaScript was not widely supported and trusted language in those days. So the world was adopting Adobe Flex to develop Enterprise Rich Internet Application and it grew a lot in 2007-2008. In 2010 Apple wrote a letter in regarding supporting flash player in Iphone, IPAD and IOS supported devices and that was not a good news for Adobe for more info click here. From that day the Big company would hesitate to build an application in Flex and search for new approach rises.

Google continued to develop an application in that approach and gave the world GMail, GMap, Google+, Picasa etc using AJAX and others followed.

What is AJAX?

AJAX stands for Asynchronous JavaScript and XML. AJAX is a technique to send the request and get data asynchronously with the refreshing web page which happens in the traditional application like Wikipedia.

With Ajax, web applications can send data to and retrieve from a server asynchronously (in the background) without interfering with the display and behavior of the existing page. – Wikipedia

XMLHttpRequest is used to make a call to server and retrieve the data. It’s an API provided by the browser to support AJAX technology.

This JavaScript code is to make ajax call to server.

Here is the php code.

And here is HTML code.

This is an example without any framework or library. Just plain JavaScript.

In next blog, it will be in more detail to make a different kind of ajax call with JQuery.

 

Understanding JMeter Results

JMeter is the best and free Performance testing tool.

When I started working on JMETER for performance testing of Code Beautify, I got confused when got the result. All JMETER results terms are gibberish to me. So I have started searching Google to find and understand what this reports wants to say. What I have learned would like to share with you.

This is a snapshot of sample JMETER results.

jmeter performance test results
Jmeter Performance Test Results

Let’s decode this results:

This an aggregated Report of JMeter having these columns Label, # Samples, Average, Median, 90% Line, Max, Min, Error %, Throughput, KB/Sec.

  • Label : Label column display HTTP request created for test. i.e for me the request is http://127.0.0.1/jsonviewer and give label as jsonviewer.
  • # Samples : Samples shows the number of http request runs for given thread. In this case jsonviewer makes 682 requests.
  • Median : is a number which divides the samples into two equal halves. Half of the samples are smaller than the median, and half are larger.
  • 90% Line : is the value below which 90% of the samples fall. The remaining samples too at least as long as the value. This is a standard statistical measure.
  • Max / Min : These are the minimum and maximum value of time required for receiving the web page.
  • Error % : This column indicated the percentage of error. For HTML Viewer made 641 requests and failed each and every request, so it gave 100% error rate. If Server is not able to serve the request, this column will help to determine the capability of the server to serve the requests.
  • Throughput : is calculated as requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server. Formula : Throughput = (number of requests) / (total time).
  • KB/Sec : The throughput measured in Kilobytes per second.

I hope this may help to understand JMeter’s results.

 

Accessing instance method of JavaScript using this keyword inside each()

As a Java or C# developer, this keyword can we be used in instance method or in constructor to access variables or instance methods.

JavaScript is a prototype-based scripting language and supports Object-Oriented features and this keyword too.

JQuery is most popular JavaScript Cross-Platform library and 99.99% developers uses it for web development. JQuery has $.each() to iterate jQuery object.

Like

In above example, when elements iterate with each, it create dynamic object inside the method named this. Now using this object we can have the access of each element. in this example using this we can get the value.

How this can be used in Javascript class. Here is the example.

Now what if we use $.each() in Javascript class and want to use <strong>this </strong>keyword as Javascript class’s instance as well as to get element in the $.each iterator?

When employee.printInfoIfSalary(10000) executed, there is no way using this or with this to call getInfo() method within each method of jQuery and it will throw uncaught TypeError: undefined is not a function.

using this Uncaught TypeError: undefined is not a function

How can we fix this? I have spent more than 1 hour to solve this problem. but finally I figured it out. Here is working code.

Working code to fix above issue.

In this example we define thisObj = this, reference of this variable to thisObj, and now thisObj can be reference as instance of this class.

I hope this example with help you to understand when jQuery and OOPs concepts needs to use together.

Code for this example:  http://codebeautify.org/htmlviewer/e1ce80

 

 

Welcome to CodeBeautify.org blog

Code Beautify helps you to beautify your code.

Make Your Code Beautiful using CodeBeautify.org

I have developed this site to keep developer as specially UI developer and designer in mind.

CodeBeautify.org will help you to test and save your code that can be share on social platform or at http://stackoverflow.com/ to get help from expert developers.

User can create an account and store code as links. If you want to make public links, Save without login.

Let us know if you want to see a new utility or want to enhance exiting utility.

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