Articles on Trending Technologies

Technical articles with clear explanations and examples

How do you validate a URL with a regular expression in Python?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 13-Jun-2020 678 Views

There's no validate method as almost anything is a valid URL. There are some punctuation rules for splitting it up. Without any punctuation, you still have a valid URL.Depending on the situation, we use following methods.If you trust the data, and just want to verify if the protocol is HTTP, then urlparse is perfect.If you want to make the URL is actually a true URL, use the cumbersome and maniacal regexIf you want to make sure it's a real web address, use the following codeExampleimport urllib try:     urllib.urlopen(url) except IOError:     print "Not a real URL"

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How to use special characters in Python Regular Expression?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 13-Jun-2020 7K+ Views

From Python documentationNon-special characters match themselves. Special characters don't match themselves −\ Escape special char or start a sequence..Match any char except newline, see re.DOTALL^Match start of the string, see re.MULTILINE $  Match end of the string, see re.MULTILINE[ ]Enclose a set of matchable charsR|S Match either regex R or regex S.()Create capture group, & indicate precedenceAfter '[', enclose a set, the only special chars are −]End the set, if not the 1st char-A range, eg. a-c matches a, b or c^Negate the set only if it is the 1st char    Quantifiers (append '?' for non-greedy) −{m}Exactly m repetitions {m, n}From m (default 0) ...

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How and why to avoid global variables in JavaScript?

Ali
Ali
Updated on 13-Jun-2020 1K+ Views

Avoid global variables or minimize the usage of global variables in JavaScript. This is because global variables are easily overwritten by other scripts. Global Variables are not bad and not even a security concern, but it shouldn’t overwrite values of another variable.On the usage of more global variables in our code, it may lead to a maintenance issue. Let’s say we added a variable with the same name. In that case, get ready for some serious bugs.To avoid the usage of global variables, use the local variables and wrap your code in closures. You can also avoid this by wrapping ...

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How to write inline JavaScript code in HTML page?

Rahul Sharma
Rahul Sharma
Updated on 13-Jun-2020 764 Views

Inline JavaScript Code − If you are adding some JavaScript code in an HTML file without using the src tag then it is known as inline JavaScript code. That’s all you need to know.

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Using datatype/element for destination in SAP ABAP

Amit Sharma
Amit Sharma
Updated on 13-Jun-2020 266 Views

You can use RFCDEST.RFCDEST statement specifies the destination value for a Remote Function Call connection and gateway information.Supported Job Types:This statement are optional for the following job types:SAP Batch Input SessionSAP Business Warehouse InfoPackageSAP Business Warehouse Process ChainSAP Data ArchivingSAP Event MonitorSAP Job CopySAP Process MonitorSAP R/3Basic DataTable  RFCDES  Destination table for Remote Function CallField  RFCDEST  Logical Destination (Specified in Function Call)Position 1Syntax to be used:RFCDEST destinationUsing Parameter destinationYou need to specify the destination for the RFC connection and gateway information for an SAP R/3 system. This destination is the destination that is specified in the connection properties file during ...

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Is it better to have one big JavaScript file or multiple light files?

Amit Sharma
Amit Sharma
Updated on 13-Jun-2020 1K+ Views

To avoid multiple server requests, group your JavaScript files into one. Whatever you use for performance, try to minify JavaScript to improve the load time of the web page.If you are using single page application, then group all the scripts in a single file.If you are using multiple files, then minify all of your scripts and separate them into categories.example - Place JavaScript to be used in every page. This can be the core script of the file. - Place your plugins hereRest, add other scripts in a JavaScript file. It’s good to maintain it in different files.

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What is the difference between a++ and ++a in JavaScript?

Krantik Chavan
Krantik Chavan
Updated on 13-Jun-2020 8K+ Views

++a returns the value of an after it has been incremented. It is a pre-increment operator since ++ comes before the operand.a++ returns the value of a before incrementing. It is a post-increment operator since ++ comes after the operand.ExampleYou can try to run the following code to learn the difference between i++ and ++i −                       var a =10;           var b =20;           //pre-increment operator           a = ++a;           document.write("++a = "+a);                       //post-increment operator           b = b++;           document.write(" b++ = "+b);          

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How to use the same JavaScript in multiple content pages?

Rahul Sharma
Rahul Sharma
Updated on 13-Jun-2020 2K+ Views

To use the same JavaScript in more than one page, add the js code in an external JavaScript file. Let’s say the following demo.js is our external JavaScript file −function display() {    alert("Hello World!"); }Now add the external JavaScript file to the following HTML web page. In the same way, you can add it to multiple content page.                                          

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How does the browser identify inline JavaScripts?

Johar Ali
Johar Ali
Updated on 13-Jun-2020 487 Views

Let’s say the following line we have in our HTML −Here the browser identifies inline JavaScript by detecting onclick, even when tag wasn’t available.The following are some of the suggestions for using inline JavaScripts −You should consider inline script elements such as ...) if the script only to be used for a single page.Do not use event attributes such as onclick="...", and bind event handlers using JavaScript.Use external script elements such as ) for most scripts, especially if reused between pages.

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What are the rules for JavaScript's automatic semicolon insertion (ASI)?

Amit Sharma
Amit Sharma
Updated on 13-Jun-2020 373 Views

JavaScript’s automatic semicolon insertion (ASI) is to insert missing semicolons. The following statements are affected by automatic semicolon insertion −empty statement var statement expression statement do-while statement continue statement break statement return statement  throw statementThe rules are in the following specification −When, as a Script or Module is parsed from left to right: A token is encountered that is not allowed by any production of the grammar, then a semicolon is automatically inserted before the offending token only if one or more of the following conditions becomes true −Offending token is }.Previous token is ) and the inserted semicolon would ...

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