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Definition of Flask url_for

Flask url_for is defined as a function that enables developers to build and generate URLs on a Flask application. As a best practice, it is the url_for function that is required to be used, as hard coding the URL in templates and view function of the Flask application tends to utilize more time during modification. If we are using hard coding, and in case we would need to change our URL by inserting another element in the URL, we would have to visit each and every template or form in the code library and make the modifications and will lead to overkill. The url_for function is capable of changing this with just a snap of fingers!

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It is time now for us to look into different syntax that is present to url_for function before we even dive into learning the working of url_for. This will help us map the syntaxes to the working methodology so that the learning is more practical and easier to grasp. So, without much further ado, let us get straight into the syntax!

Creating dynamic URL with no key passed:

Note: We need to make sure that the function name doesn’t carry any argument, else it might lead to an error.

Creating a dynamic URL with a key and corresponding value passed:

Redirect to a URL using Flask (assuming we are passing key and value pair):

How does url_for work in Flask?

In this section let us go through the working of url_for in Flask, but before that, it is very much required to know about the need for building URLs using the reversing function url_for( ). The concept of reversing function is to use meaningful URLs to help users. If the web application is able to create a meaningful URL that consists of inputs from users, users may remember the inputs used and will enhance the return to the same page again. Not only this there are other pointers that we will discuss below which signifies the importance of using a dynamic URL, keeping in mind the inputs of the user, instead of hard coding the URL.

Developers can change the content of the URL in one shot, and there is no dependency on remembering locations to manually change the hard-coded URLs.

The process of reversing is more descriptive than hard coding.

The special characters and Unicode data are efficiently handled in case of using dynamic URLs.

This is the easy way to avoid unexpected behavior of relative paths in browsers by allocating absolute paths to the generated URLs.

In the case of an application placed outside URL root, the url_for( ) function is capable of handling such scenarios.

Now that we have an understanding of why url_for( ) is so widely appreciated, we would need to understand the types of View responses, as one of these responses relates to the work of url_for( ). The big 3 ways of route logic, an act of mapping the URLs to their specific actions, are namely generating a page template, providing a response, and redirecting the user to a specified location. The working of url_for( ) falls under the category of redirecting.

The method of redirecting accepts a string and this string is nothing but the path that the user is directed to. For the same, the routes are referred to by their names and not by their URL patterns. In the process of creating this input for the redirect function, we use url_for( ). The function url_for( ) takes the name of the view function as an input and creates an output of the provided view. With the change of route URLs, there will be no broken links between pages. Now, when a view is registered with the @app.route decorator, the endpoint name is determined and is ready to be stored with the route registration. This stored route registration is then used to find all routes which link to the registration with the name along with the parameters passed and then execute them to reveal the output.

One important thing to be kept in mind is that, in case we have registered 2 different functions under the same name, we are bound to get an AssertionError and for the same, we can take the help of the endpoint variable and specify the needful. With this, we complete the working of the url_for( ) function in terms of URL routing.

It’s now time for us to look at the implementation of url_for in a Flask application!

Examples

Now that we have complete knowledge about the implementation of url_for and the working methodology along with a complete view on syntax, in this section, we will try using them in practice so that it is easier to learn them by knowing what the practical output will look like! In the examples, we would look at using test_request_context( ) so that we can realize it on the python shell on what URL the particular command is routed to.

Example #1

Creating dynamic URL with no key passed (Run it on console)

from flask import url_for, Flask appFlask = Flask(__name__) @appFlask.route('/home') def home(): return 'We are in Home Page!' with appFlask.test_request_context(): print(url_for('login'))

Output:

Example #2

Creating a dynamic URL with a key and corresponding value passed

Syntax:

from flask import url_for, Flask appFlask = Flask(__name__) def profile(authorname): return f'{authorname}'s profile' with appFlask.test_request_context(): print(url_for('profile', authorname='EduCBA')) print(url_for('profile', authorname='EduCBAPremium'))

Output:

Here, we can easily see the distinction when 2 different values are passed using parameters

Example #3

Syntax:

from flask import Flask, redirect, url_for appFlask = Flask(__name__) def accountType(Type): return 'This is a %s account' % Type def userType(name): if name =='premium': return redirect(url_for('accountType',Type = name)) else: return redirect(url_for('accountType',Type = name)) if __name__ == '__main__': appFlask.run(debug = True)

Output:

When the type is Premium account type:

When the type is basic account type:

Conclusion

Herewith in this article, we have got an essence of how URL routing happens and what dynamic URL can bring to the table. With this, we encourage our readers to experiment with notes in the article and build an exciting Flask application!

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How Does Laravel Permissions Work With Examples

Introduction to Laravel Permissions

Laravel is one of the most sought after frameworks for E-commerce development. The reason for this popularity being the ease of usage. Laravel allows the developer of the scope of creating complex structures and functionalities using simple and expressive syntax. Laravel is scalable and that is the reason why E-commerce site owners prefer to use it. This gives them a wide range of options to choose from for catering to demanding customers. Laravel is known for its vast library of queries which provide all that is needed for quick development. The framework is also capable of integrating with third-party queries to form standalone systems.

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One such query that makes development easy is Laravel Permissions.

What is Laravel Permission? How does Laravel Permission work?

Through Roles and Permissions, one can create several types of users with different roles and permissions, some users will only have view access, some users can also edit items, some can go ahead and delete. Access is usually provided by the Super Admin.

Example #1

Installing the tool: The migration needs to be run: PHP artisan migrate

1. The HasRole needs to be added to the User Model:

class User extends Authenticatable { use HasRoles; ... }

2. It now has to be loaded into the Tool for the Roles to be displayed:

public function tools() /* defining the function tools */ { return [ new NovaToolPermissions(), ]; }

3. Adding an additional relationship if roles are to be assigned from the User resource:

public function fields(Request $request) { return [ ... BelongsToMany::make('Role', 'role', Role::class), ]; }

4. Since we are using the Nova Tool for permission, the viewNova Gate default can be replaced with Gate():

protected function gate() { }

5. This program comes with default permissions:

"viewNova": "viewRoles": "manageRoles": "assignRoles": "viewUsers": "manageUsers":

6. It is pertinent to know that, routine permission is required for certain sections. This is to ascertain that only the correct authority has access to the sections of the blog or the whole blog.

For example, the policy related to the blog: PHP artisan make: policy BlogPolicy Now the policy needs to be assigned:

class AuthServiceProvider extends ServiceProvider { use ValidatesPermissions; protected $policies = [ ]; public function boot() { collect([ 'viewBlog', 'manageBlog', Gate::define($permission, function ($user) use ($permission) { return true; } }); }); } }

7. Final step. Access control has to be specified in the policy:

use IlluminateSupportFacadesGate; public function viewAny($user) { return Gate::any(['viewBlog', 'manageBlog'], $user); } public function view($user, $post) { return Gate::any(['viewBlog', 'manageBlog'], $user, $post); } public function create($user) { } public function update($user, $post) { } public function delete($user, $post) { } public function restore($user, $post) { } public function forceDelete($user, $post) { }

8. Now add labels:

{ "viewBlog": "View Blog", "manageBlog": "Manage Blog" }

Output:

This one is for the Edit Role:

The Role would now need to be assigned.

Example #2

Another quick example:

Install: Install it into the Laravel application which uses Nova through composer. Register the provider in case you have the package discovery disabled. It will be registered in the config/app PHP file as shown below:

NovaPermissionServiceProvider::class, ]

1. Now tool needs to be registered as shown below:

/*defining tools method */ public function tools() { return [ /*…*/ LaravelNovaPermission::make(), ]; }

2. Now, the addition of Morph To Many to the resource as follows:

use LaravelNovaFieldMorphToMany; /*defining method*/ public function field(Request $request) { return [ /* ...*/ MorphToMany::make('Role', 'role', Role::class), MorphToMany::make('Permission', 'permission', Permission::class), ]; }

3. Now, adding class ForgetCachedPermissions to the config/nova.php as follows:

/* config/nova.php */ /*Registering middleware*/ ‘web’, /*adding different classes*/ DispatchServingNovaEvent::class, Authenticate::class, Authorize::class, BootTools::class, ForgetCachedPermissions::class, ],

4. Artisan command line can be used for localization files publishing: vendor: publish. Usage of Custom Role:

/*app/Providers/NovaServiceProvider.php*/ /*defining tools method */ public function tools() { return [ /* ...*/ LaravelNovaPermission::make() ]; }

5. Changing the default Authorization (Policy-based) to Permissions based Authorisation:

/* app/Nova/MyNovaResource.php*/ class MyNovaResource extends Resource { use PermissionsBasedAuthTrait; /* defining array*/ public static $permissionsForAbilities = [ ]; } public static $permissionsForAbilities = [ ];

Output:

Here one can create Roles and give access to users as well as to others who would have defined Roles. It is imperative to remember that at the top of the Access control Hierarchy, sits the Super Admin. The Role of the Super Admin is to provide definite access control authorizations for specific responsibilities. Developers need to be careful while creating ACL or Access Control Lists, since a wrong move here may lead to jeopardizing the entire project.

Steps to Provide Laravel Permissions

Another way to provide permissions is:

Step #1

PHP artisan make: seeder PermissionSeeder

Step #2 <?PHP use IlluminateDatabaseSeeder; use SpatiePermissionModelsRole; use SpatiePermissionModelsPermission; class PermissionSeeder extends Seeder { /** * Run the database seeds. * @return void */ public function run() { $roles=[ 'admin', 'accountant', 'user' ]; $permissions=[ ]; foreach ($roles as $role) { } foreach ($authorized_roles as $role) { } } } }

Add role to the Users

Go ahead and refresh the database:

php artisan migrate: fresh –seed

Conclusion

Laravel Permission is important from the perspective of access control. An access control list is a concise set of information authorising users for a certain level of access. Laravel Permissions work on the basis of hierarchy. Developers will be given a higher level of access than front end users.

The administrator of the site will be provided with greater access. The final access rests with the Super Admin. He/she will be the one providing everyone with the Roles and their access limits.

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How Does Linux Read Command Work With Examples

Introduction to Linux Read Command

In the Linux ecosystem, the read command is used to read from the file descriptor. In other words, the read command is mostly used in the bash environment. In bash, the read command is used for the word segmentation of the string under the Linux environment. The read command is a built-in utility available in the Linux ecosystem.

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Syntax:

read [options] [name...]

read: We can use the read keyword in the syntax or command. It will accept the two arguments as input i.e. the options and name. As per the requirement, the read command will do the word segmentation of the string.

options: We can provide the different flags as options that are compatible with the read command.

name: The read command, the name parameter will specify to store the actual words from the split operation.

How Does Linux Read Command Work?

Basically the read is a built command in the Linux environment. It has come with the basic operating system packages. Hence there is no need to add any additional packages in the Linux environment.

Option Description

-l It will display all the names of Readline functions in the environment.

-p It will print the readline function names and the bindings that they can be re-read.

-P It will display the current readline function names and bindings in the environment.

-s It will print the readline key sequences bound to macros as well as the strings output. The outputs will then re-read.

-S It will print the readline key sequences bound to macros as well as the strings output.

-v It will print the readline variable names and the values. The output can be re-read.

-V It will print all the current readline variable names and values available in the environment.

Examples to Implement Linux Read Command

Below are the examples of Linux Read:

#1. Read Command

In read command, we are able to read in the user inputs. The same input we can pass to different commands or jobs. So, in the next instance, the different commands or the jobs can perform the execution operation with the read command as in input.

Note: To access the read command value, we can use or call the system variable “REPLY”.

Command:

read

Explanation: The read command can accept user input. Just we need to right the read command and enter the input message or variable value (refer screenshot 1 (a)). By default, the message will store in the system variable. When we will call the system variable “REPLY”. The entered message will display (refer screenshot 1 (b)).

Output:

echo $REPLY

#2. Read Command with variable

In the Linux environment, we are having the functionality to access the read command value in different variables. As per the requirement, we can define the variable in the read command.

Note: there is no need to call the system generated variable “REPLY”.

Command:

read variable1

Explanation: As per the above read command, we are forcefully using the own variable to store the input value (refer screenshot 2 (a)). The same variable will use to see the read command message (refer screenshot 2 (b)).

Note: Here the read command message will not store in the “REPLY” variable.

Output:

echo "$variable1"

#3. Read Command in Shell Mode

Command:

echo "Which topic is it?";read a;echo "Welcome to $a"

Explanation: In live shell mode, we can also use the read command. It will ask the user input. Once the user will enter the input value. It will print the message as per the read command output.

Output:

#4. Read Command with “-p” Option

In read command, we are having the functionality to provide the hint while entering the user inputs in the shell prompt. For providing any hint on the shell, we need to use the “-p” option with the read command.

Command:

read -p "Please Enter Your Mobile No : "

Explanation: As per the above command, we are giving hit to the end-user for entering the relevant character. It will help to give an important message while entering any user input.

Output:

#5. Read Command with “-n” Option

In read command, we are having the functionality to restrict the specific number of characters. For restricting the number of characters, we need to use the “-n” option with the read command.

read -n 6 -p "Enter Pin Code : "

Explanation: In the above command, we are restricting the user input with a specific threshold (we have used the 6 characters). If the character will excide more than 6 then the prompt will automatically vanish.

Output:

#6. Read Command with “-s” Option

In read command, we can secure sensitive data. While entering critical information, we can hide the information. To secure the critical information, we need to use the “-s” option with the read command.

Command:

read -s -p "Enter Password : "

Explanation: As per the above read command, we are accepting the user input in a secure way. The user input will not display on screen but the read command is accepting user input.

Output :

Conclusion

We have seen the uncut concept of “Linux Read Command” with the proper example, explanation, and command with different outputs. The read command is widely used in shell and application-level jobs. We can use the read command in different ways like accepting user inputs, secure input, character restriction, input hint, etc.

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How Does Masking Work In Css? (Examples)

Introduction to CSS Masking

CSS Masking masks images or elements by completely hiding them or making certain portions of the image invisible, using various levels of opacity. In CSS, you can achieve masking by using the mask-image property, which applies a mask to the text content and background. Masking is a graphical operation that conceals a specific part of an image, allowing the background to show through the mask. It applies to both HTML and SVG images, as well as elements with multiple layers.

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Syntax:

With this CSS, the mask is find using #mask Id.

Where mask – reference is img or mask source, the # tag states any number of mask references separated by a comma. Multiple images follow the Stack property rule.

How Does Masking Work in CSS?

You can use a masked image to apply a color blur or mask the properties of an element by utilizing the filter. This Masking partially conceals the visual elements. Files like PNG, CSS gradient and a few SVG utilize masking to hide specific parts of an image or another element on the page. The CSS mask property achieves this masking effect.

This masking technique makes web design interesting and flexible, eliminating the need for manual image alterations when creating new ones. We use a few properties here, like mask image, mask mode, mask repeat, mask position, mask clip, mask origin, and mask size. So this mask is applied either to an entire element or sometimes excluding border padding.

1. mask-image Property: This sets a layer in the image element by setting this with a URL value. So this can be referenced as a path of the image file to be masked. We need an image link file that is going to be masked. Any number of mask image layers can be added, and commas separate it. Example: The below example references the PNG file.

masked-element { mask-image: url(pic.png); }

We need two URL values to set more than one mask image layer. Here, we observe the process of combining two masks.

.double mask { mask-image: url(pic.png),url(pic.png); }

Next, using Gradient-image, which is well suited for this property

. masked-element { mask-image: linear-gradient (black 0%, white 0%,transparent 100%); }

2. mask-size: This sets the pixel value over here. This is an important case to create the effect.

3. mask-repeat: This has different effects like space, round to spread across the area. This has only one mask with it.

Types of CSS Masking

There are two types of masks. They are:

luminance

alpha

Luminance Masking: In this type, an image is transformed into a Grayscale type. If a portion of a mask is lighter, the more of the mask is visible. Black indicates Full Transparent, and Gray specifies partial transparency.

Alpha Masking: Alpha is the Default mask. This is the same as Luminance Masking except in the Opaque portion of an element. In both cases, Transparency matters.

Examples to Implement CSS Masking

In this section, we shall discuss how to show CSS masking capabilities. Using the Chrome browser is highly recommended.

Example #1

Demo showing an example for Gradient along with text masking

body { color: yellow; font-size: 1.2em; font-family: 'calibri', Helvetica, Arial, sans-serif; } p { padding: 1.2em; color: white; } margin: 21px auto; max-width: 660px; height: 300px; margin: 32px auto; overflow-y: scroll; background: url(floral1.png) no-repeat; -webkit-mask-image: linear-gradient(black, transparent); mask-image: linear-gradient (black, transparent); }

Code:

Russia has natural beauty on nature which has a list of travel destinations around them. They too celebrate a nature protection day. Russia has majestic lakes, mountains and rivers. Russia has natural beauty on nature which has a list of travel destinations around them. They too celebrate a nature protection day. Russia has majestic lakes, mountains and rivers. Russia has natural beauty on nature which has a list of travel destinations around them. They too celebrate a nature protection day. Russia has majestic lakes , mountains and rivers. Russia has natural beauty on nature which has a list of travel destinations around chúng tôi too celebrate a nature protection day. Russia has majestic lakes , mountains and rivers.

Output:

Example #2

Masking with the help of borders.

Code:

HTML CSSResult EDIT ON

chúng tôi

img { width: 300px; margin: 30px; } .normask { mask: url("floral1.png"); } .bordmask { -webkit-mask-box-image: url("floral1.png") 20 repeat; mask-border: url("floral1.png") 20 repeat; } body { transform-origin: top right; transform: scale(0.8); white-space: nowrap; overflow: hidden; }

The left side is the original image. The right side shows how the two images masked.

Output:

Example #3

This implementation shows applying a mask to an image. The mask used here is alpha. The image fills the black area.

body { background-color: black; color: pink; font-size: 1.2em; font-family: 'Calibri', Helvetica, Arial, sans-serif; } img { margin: 30px auto; display: block; width: 90%; height: 300px; -webkit-mask-position: centercenter; mask-position: centercenter; -webkit-mask-repeat: no-repeat; mask-repeat: no-repeat; }

mask2.html

HTML CSS Making Black color

Output:

Example #4

Image Stretches using a mask.

ppp.html

chúng tôi

body { width:100%; margin:0; } .stretch { width: 90%; height:100vh; background: url("cind.png"); background-size: cover; position: absolute; } .para { width: 110%; height: 150vh; } .title { font-family: Impact, 'Arial Narrow Bold', sans-serif; font-size: 300px; color: white; position: fixed; top:21vh; width:100%; text-align: center; text-shadow: 2px 2px 12px rgba(0,0.1,0,0.1); } .exmask { mask:url("sketch.png"); mask-size: cover; -webkit-mask:url("sketch.png"); -webkit-mask-size:cover; width:100%; height:100%; }

Output:

Conclusion

Coming to the final thoughts, this article has covered approaches to masking objects in CSS and depends on the purpose. Also, we have seen their properties and demo of them. And when building masks, their border property and multiple backgrounds have the power.

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How Does Rsync Work In Linux With Example?

Introduction to Linux Rsync

Rsync is a utility in the command line which enables users to transfer and synchronize files efficiently between a computer and an external hard drive in the entire connected network. This utility is achieved by comparison of modification times and also the file size. This utility of the synchronization is written in C language, and this application executes as a single-threaded application. Another term you would hear a lot when someone talks about rsync is that this utility is a delta encoding. Delta encoding essentially a way of storage or transmission of data as a difference of the files or, in other terms, sequential data. This utility needs to be set up between the user and the host, and once the sync is set, thus utility will itself determine parts of the local file that needs to be transferred between them to keep the sync. In this topic, we are going to learn about Linux Rsync.

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Syntax

Before we even jump into understanding what scenarios rsync would help or the working principle of rsync, it is beneficial to understand the syntax behind the rsync. Then, while going through the working principle, we can keep the syntax in mind.

OR

The usage of any of the above syntax solely lies in the developer’s level of comfortability and confidence. Therefore, there is no benefit difference in using any syntax over the other. If you notice carefully, the difference only lies in the way the source address is mentioned, and each individual has their level of confidence on which one to be used, and hence the utility in the corresponding ways.

Here, SOURCE is the place where the files or directory will be copied from, and DESTINATION is the place where the files and directories get copied into. Now, these 2 parameters or arguments are the mandatory ones, whereas the ones in square brackets “[]” are optional and can be used as per the requirement of the functionality being developed. Next, we will talk about the majority of the options which are used extensively in the industry nowadays.

How does rsync work in Linux?

In the introduction, we already learned that rsync is a command-line utility that helps in synchronizing Unix clients present in the network. This utility comes in very handy in scenarios like backing up the files in a system to another system which is housed only for backing up the files. Rsync utility also has the capability to run in daemon mode, a mode that allows the application to run in the background rather than run under the active control of a user. Daemon mode out of scope for this article, but as an interesting fact, the syntax is read as: rsync://

From here, we will look at different OPTIONS we talked about in the syntax one by one, and we will try to accompany each OPTION or a combination of OPTIONS with a code snippet and the output that is expected corresponding to it!

OPTION Where will it be used?

-v, –verbose This option is used if the user wants to know what exactly the computer is doing while executing the command.

-q, –quiet If the user doesn’t need the output message, this option can be used for suppressing the outputs.

-a, –archive This option can be used to archive files when synchronization is taking place.

-r, –recursive For recursively syncing the files and directories, this option can be used.

-b, –backup While the synchronization is taking place, if the backup of the files or delta is needed, even if there is a loss in communication, data leakage can be minimized.

-u, –update If the user doesn’t want the files at the destination to not update if the files there are newer than the source, this option can be used to successfully implement the use case.

-l, –links This option is used in scenarios where symbolic links (symlinks) should be copied as symlinks only.

-n, –dry-run This option is used when we would need to do a trial run without actual synchronization. This is done so that we understand the use case we are trying to solve and if the solution implemented actually caters to the problem.

-e, –rsh=COMMAND When this option is used, an alternative remote shell program is used for communication between the remote and local copies.

-z, –compress To minimize the data consumption during synchronization, this option can be used to compress the file being sent.

-h, –human-readable To display the output in a human-readable format for interpretation, this option is used.

–progress When the sync’s progress needs to be shown as an output, this option comes in very handy!

–remove-source-files In some cases, one would like to delete the file at the source so that there is no duplication of the files and space can be kept optimized. This is the option to get that utility!

Examples of Linux Rsync Example #1

LOCAL COPY OR SYNC OF FILES

Code:

mkdir backup ls -l ./backup/ rsync -zvh chúng tôi ./backup/ ls -l ./backup/

Output:

In this scenario, we have utilized the combination of options listed above to have a verbose (-v) output during the rsync execution. In the highlighted version, the output is changed to a more human-readable format (-h). Also, during transfer, the text file was zipped (-z) so that the data transfer can be optimized to the maximum.

Example #2

Code:

ls -l rsync -zvh--remove-source-files chúng tôi ./backup/ ls -l

Output:

In the case of, we see that chúng tôi was present in the working directory in the initial instance. After the synchronization is complete, when we do an ls command, we see that the file has been moved from there to the new location as specified in the command, i.e. Backup.

Conclusion

In this article, we have gone through various options that are possible through the use of rsync in general. In cases of performing rsync on different IPS, only the user and the IP address of systems need to be added extra to complete the utility.

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How Python Eval Function Work With Examples

Introduction to Python eval()

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Syntax:

eval(expression, globals=None, locals=None)

Explanation:

Eval() function usually needs 3 parameters, but the 2nd and 3rd parameter terms are optional/not much important than the 1st parameter. The 3 parameters are expression, globals, and locals.

Expression parameter: This is the string that is as parsed and also evaluated as the Python expression.

Globals parameter ( dictionary parameter ): This parameter is a dictionary, and this parameter is also optional. Nothing happens even if we don’t specify this parameter in the eval() function.

Locals parameter ( Mapping Object ): This locals parameter is an object which is mapping… The dict or dictionary of the globals parameter is the best and standard mapping type in the Python Programming Language commonly.

How Python Eval Function Work with Examples

Eval() function/method will returns the value/result after evaluating the expression. eval function works by parsing the string value, and that string value also be evaluated as the python expression.

Example #1

At each and every IF statements, if the IF condition is False, then the interpreter of python goes to the ELSE condition’s statements, and the programming inside of it will be printed/interpreted etc.. all at a time, but the program inside of the ELSE condition is also be interpreted every line one by one.

Code:

x = 10 print(eval('x')) print(eval('x+10')) print(eval('x*x')) print(eval('x*x*x')) if(x%2==0): print('X is even number') if(x%2!=0): if(x%3!=0): if(x%5!=0): if(x%7!=0): print(eval('x')) print('is a prime number') else: print ('x is not prime number') else: print('x is not prime number') else: print('x is not prime number') else: print('x is not prime number')

Output:

Example #2

Now we enter the try, except concept. These are just like the IF and ELSE condition. If the “try” has correct parameters, then try to run properly and exits from the program, or else the except concept comes into the picture. Try, except concept will be very helpful to handle errors and usage of the eval() function/functions. Statements that are in the try will print the eval() function, which has math functions “square root” and the power of x and y values which are about to declare manually by the user. If the input doesn’t contain any input as needed with the mentioned math functions, the result will be printed, and the loop once again runs and asks again for the input, or else you can just enter and go the except concept. There you will print the ext1 value, and the interpreter breaks out and comes out from the except concept. Then the print statement will print “Now it is Done” like that.

Code:

from math import * for lm in range(1, 3): func1 = input("Enter the Math Function which are mentioned below to Evaluate.nFunctions Allowed are: 1. square_root(x) and 2. power(x,y):n") try: print(eval(func1, {'square_root': sqrt, 'power': pow})) except Exception as ex1: print(ex1) break print('Now it is Done')

Output:

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This is a guide to Python eval(). Here we discuss the introduction and working of the python eval() function along with different examples and its code implementation. You may also look at the following articles to learn more –

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