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Definition of PostgreSQL JSON

JSON is an abbreviation of JavaScript Object Notation. JSON stores value in key-value pair; it is an open standard format. We generally prefer JSON for sending/receiving or exchanging data between servers and in web applications. The data within JSON is in text format, which is easily human-readable. PostgreSQL version 9.2 introduced support for the native JSON data type. PostgreSQL provides various methods and operators to work with JSON data.

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Syntax:

column_name json  How JSON Works in PostgreSQL?

We need to make sure the given data is in a valid JSON format before adding it to the table.

If JSON data is incorrect, then it will throw an error.

PostgreSQL provides the two native operators to work with JSON data.

How to Insert JSON Data?

To understand the insertion of JSON data, let us create a ‘student’ table with the following structure.

The student table consists of two columns:

stud_id: The column is the primary key column that uniquely identifies the student.

stud_data: The column which stores the student’s information in the form of JSON.

Let’s create the table by using the CREATE TABLE statement:

CREATE TABLE student ( stud_id serial NOT NULL PRIMARY KEY, stud_data json NOT NULL );

Now we will insert the data into the stud_data column, which is of type JSON. Before adding JSON data to the table, we need to ensure the given data is invalid in JSON format. Now insert the JSON data with the help of the following INSERT statement, which will add a new row into the ‘student’ table.

INSERT INTO student (stud_data) VALUES ( '{ "name": "Oliver Jake", "information": { "mobile_number": "9999999999", "branch": "Computer", "rank":12 } }' );

After executing the above statement, illustrate the student table’s content using the following snapshot and SQL statement.

select * from student;

Output:

We can insert multiple rows in the table using the following INSERT statement:

INSERT INTO student (stud_data) VALUES ( '{ "name": "Jack Connor", "information": { "mobile_number": "9999999910", "branch": "Computer", "rank":1 } }' ), ( '{ "name": "Harry Callum", "information": { "mobile_number": "9999999911", "branch": "Civil", "rank":2 } }' ), ( '{ "name": "Jacob John", "information": { "mobile_number": "9999999912", "branch": "Electrical", "rank":6 } }' ); select * from student;

We can fetch the data from the student table by using the following snapshot and SQL statements.

Output:

Examples of PostgreSQL JSON

We have created a student table in the above section; let’s use the same for understanding the following examples.

Example #1 – Get all students in the form of JSON key SELECT FROM student;

Output:

Example #2 – Get all students in the form of JSON text SELECT FROM student;

Output:

Example #3 – Get specific JSON node using operators SELECT FROM student ORDER BY rank;

Output:

Example #4 – Use JSON operator in WHERE clause

In order to filter rows from the result set, we can use the JSON operators in the WHERE clause. Consider the following example, which gives us the record whose branch is Computer by using the following statement.

SELECT FROM student WHERE

Output:

Example #5 – PostgreSQL JSON functions

PostgreSQL provides us with some functions to handle JSON data.

json_each function

By using the json_each() function, we can expand the outermost JSON object into a set of key-value pairs as follows:

SELECT json_each (stud_data) FROM student;

We can use the json_each_text() function to get a set of key-value pairs as text.

json_object_keys function

We can use the json_object_keys() function to get a set of keys in the outermost JSON object as follows:

SELECT FROM student;

json_typeof function

With the help of the function json_typeof(), we can get the type of the outermost JSON value as a string. The type of JSON value can be a boolean, number null, string, object, and array.

We can get the data type of the information using the following statement:

SELECT FROM student;

Output:

We can get the data type rank field of the nested information JSON object using the following statement:

SELECT FROM student;

Output:

Advantages of using JSON in PostgreSQL

Advantages of using JSON in PostgreSQL are given below:

Avoid complicated joins.

Parsing of JSON data is quite easier and faster execution.

Compatible with various database management systems.

Javascript Notation Objects are faster and very easy to read and understand.

The data within the JSON object is separated by a comma, making it easily understandable.

JSON is lightweight for data exchange.

Conclusion

From the above article, we hope you understand how to use the PostgreSQL JSON data type and how the PostgreSQL JSON data type works to store the data in key-value pair. Also, we have added some examples of PostgreSQL JSON to understand it in detail.

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How Json Works In Redshift With Examples?

Definition on Redshift JSON

Redshift JSON has limited support while working with the JSON documents in redshift, basically, there are three types of options available in redshift to load the data into table. First option is we can convert the JSON file into relational model before loading data into the redshift, to load the data using this options we need to create the relational target database. Second option is load all the JSON documents in redshift table and query those documents using JSON functions, there are multiple JSON function available in redshift to query the data of JSON documents.

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Syntax

Below is the syntax of JSON in redshift are as follows.

2) Select json_function (name_of_json_column,) group by, order by

Parameter description syntax of redshift JSON.

1) JSON function – This is the function which was we have using with JSON data to retrieve from JSON column. There are multiple JSON function available in redshift to query the JSON data. We can retrieve the JSON column data using JSON function in redshift.

2) Select – Select command is used with JSON function to retrieve data from table by using the clauses and conditional operator.

3) Name of column – This is the name of JSON data column which was we have using with JSON function to retrieve data from table.

4) Value of json column – This is nothing but the column value which was we have using to segregate the JSON document data in redshift. We can segregate the data from table column as per value which was we have used in our query.

5) Where condition – We can retrieve JSON document from column by using where condition in redshift.

6) Order by condition – We can retrieve JSON document from column by using order by condition in redshift.

7) Group by condition – We can retrieve JSON document from column by using group by condition in redshift.

How JSON works in Redshift?

There are multiple options available to load the JSON documents in redshift. After loading the data we can retrieve the JSON data by using following JSON functions.

6) Json extract array element text (JSON_EXTRACT_ARRAY_ELEMENT_TEXT) function.

If we want to store the small number of key-value pairs then JSON document is best suited for the same. Using JSON format we can save the storage space of storing the data.

We can store multiple key value pair in a single column by using JSON format, we cannot stored multiple key-value pair in other format.

To use the JSON function on integer datatype values or the data which was not in JSON format. We can apply JSON function only on JSON type of document.

Below example shows that we can apply JSON function only on JSON type of columns.

Code:

Select json_extract_path_text (stud_name, 'A') as key2 from redshift_json where stud_id = 101;

In above example, we have applied JSON function on stud_name column and trying to retrieve key-value pair as “A”, But it will showing error as invalid JSON object which was we have used in our query.

Also, it will showing the parsing error of query.

We cannot use the integer datatype column with JSON function in redshift, we need to use only JSON type of data.

Below example shows that we cannot use the integer datatype of column with JSON function in redshift.

Select json_extract_path_text (stud_id) from redshift_json where stud_id = 101;

In above example, we have used column name as stud_id with JSON function, stud_id datatype as integer. So it will issues the error like integer does not exist, which was not found any matching function or arguments.

We can use copy command to load the data from JSON file to redshift table. We can also use the JSON files which was stores in the S3 bucket.

We can also copy JSON file fields automatically by using option as auto or we need to specify the path of JSON file.

Examples

Below is the example of JSON in redshift are as follows.

1) Querying JSON fields using IS_VALID_JSON function

The below example shows querying JSON fields using IS_VALID_JSON function are as follows. This function is validates the JSON string.

In below example, we have used JSON column to validate the JSON data from function. We have not found any invalid JSON data in JSON column.

Code:

Select stud_id, json, is_valid_json (json) from redshift_json order by stud_id;

2) Querying JSON fields using is_valid_json_array function

Below example shows querying JSON fields using is_valid_json_array function are as follows. This function validates the JSON array string.

In below example, we have used JSON column to validate the JSON array value from function. We have not found any JSON array in JSON column.

Code:

3) Querying JSON fields using json_extract_path_text function

Below example shows querying JSON fields using json_extract_path_text function are as follows. This function is extracting the value from the text.

In below example, we have used json column to extract path text data from function.

Code:

Select stud_id, json, json_extract_path_text (json, 'key2') as json_key from redshift_json order by stud_id;

4) Querying JSON fields using json_parse function

Below example shows querying JSON fields using json_parse function are as follows. This function is used to parse the JSON value.

In below example, we have used json column to parse the data from function.

Code:

Select stud_id, json, json_parse (json) as json_key from redshift_json order by stud_id;

Conclusion

We can use multiple JSON function to query data from table columns. Redshift JSON is very useful and important to store the value in key-value pairs. Using JSON we can store multiple column value within a single column. We can also minimize the storage usage using JSON in redshift.

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How Do I Write Json In Python?

In this article, we will learn different types of methods to write JSON in python.

Conversion Rules

When converting a Python object to JSON data, the dump() method follows the conversion rules listed below −

Writing Dictionary into a JSON File

The function of json.dump() is to arrange a Python object into a JSON formatted stream into the specified file.

Syntax dump(obj, fp, *, skipkeys=False, check_circular=True, allow_nan=True, indent=None, separators=None, default=None, sort_keys=False, **kw) Parameters

obj − obj is known as object that arranges as a JSON formatted stream.

fp −the fp also know as file object will store JSON data.

skipkeys − The default value is False. It ignores the Keys of dict that are not of a basic type. Orelse, it will throw a TypeError.

check_circular − It’s default value is True. It’s main task is to perform circular reference check for container types. This sometimes get the output result in an OverflowError.

allow_nan − It’s e default value is True. If false, serializing out-of-range float values will result in a chúng tôi uses JavaScript equivalents like -NaN, Infinity, -Infinity by default.

indent − It is used for good printing with a specified order.

separators − These are the ones used in the JSON.

default − this function is called when an object fails to serialized. It either returns object’s JSON-encoded version or throw a TypeError. If no type is given, a TypeError is defaulty thrown.

sort_keys − It’s default value is False. If true, the dictionaries’ output will be ordered/sorted by key.

Example

The following program converts the given dictionary to a JSON file using the json.dump() function −

# importing json module import json # creating a dictionary inputDict = { "website": "Tutorialspoint", "authorName": "xyz", "Age": 25, "Address": "hyderabad", "pincode":"503004" } # opening a JSON file in write mode with open('outputfile.json', 'w') as json_file: # writing the dictionary data into the corresponding JSON file json.dump(inputDict, json_file) Output

On executing, the above program will generate the following output −

{"website": "Tutorialspoint", "authorName": "xyz", "Age": 25, "Address": "hyderabad", "pincode": "503004"}

A file named outputfile.json is created containing the above dictionary data.

Using the Indent Parameter

Use the indent parameter of the method dump() for attractive printing.

Example

The following program converts the given dictionary to a pretty JSON file with indentation using the json.dump() function and indent argument −

# importing JSON module import json # creating a dictionary inputDict = { "website": "Tutorialspoint", "authorName": "xyz", "Age": 25, "Address": "hyderabad", "pincode":"503004" } # opening a JSON file in write mode with open('outputfile.json', 'w') as json_file: # writing the dictionary data into the corresponding JSON file # by adding indent parameter to make it attractive with proper indentation json.dump(inputDict, json_file, indent=5) Output

On executing, the above program will generate the following output −

{ "website": "Tutorialspoint", "authorName": "xyz", "Age": 25, "Address": "hyderabad", "pincode": "503004" }

A file named outputfile.json is created containing the above dictionary data with a proper indentation for making it more pretty.

Sorting the Keys in JSON

We can sort the keys of a dictionary alphabetically using the sort_keys = True parameter.

The following program converts the given dictionary to a sorted JSON file with indentation using the json.dump() function and sort_keys argument−

# importing JSON module import json # creating a dictionary inputDict = { "website": "Tutorialspoint", "authorName": "xyz", "Age": 25, "Address": "hyderabad", "pincode":"503004" } # opening a JSON file in write mode with open('outputfile.json', 'w') as json_file: # writing the dictionary data into the corresponding JSON file # indent parameter- to make it attractive with proper indentation # sort_keys- sorts the dictionary keys alphabetically json.dump(inputDict, json_file, indent=5, sort_keys=True) Output { "Address": "hyderabad", "Age": 25, "authorName": "xyz", "pincode": "503004", "website": "Tutorialspoint" }

The keys are now sorted alphabetically, as seen above.

Separators are an additional argument that can be used. In this, you can use any separator you like (“, “, “: “, “,”, “:”).

Converting Python List to JSON Example

The following program converts the python list to JSON string using dumps() function −

# importing JSON module import json # input list inputList = [2, 4, 6, 7] # converting input list into JSON string using dumps() function jsonString = json.dumps(inputList) # printing the resultant JSON string print(jsonString) # printing the type of resultant JSON string print(type(jsonString)) Output [2, 4, 6, 7] Converting Directories Python List to JSON Example

The following program converts the Directories python list to JSON string. using dumps() function −

# importing json module import json # input list of dictionaries list_dict = [{'x':10, 'y':20, 'z':30}, {'p':40, 'q':50}] # converting list of dictionaries into json string jsonData = json.dumps(list_dict) # printing the JSON data print(jsonData) Output [{"x": 10, "y": 20, "z": 30}, {"p": 40, "q": 50}] Converting Python List of Lists to JSON Example

The following program converts the Python List of Lists to JSON string using dumps() function −

# importing JSON module import json # input list of lists list_of_list = [[{'x':10, 'y':20, 'z':30}], [{'p':40, 'q':50}]] # converting a list of list into JSON string jsonString = json.dumps(list_of_list) # printing the resultant JSON string print(jsonString) Output

[[{"x": 10, "y": 20, "z": 30}], [{"p": 40, "q": 50}]]

Conclusion

This article contains a variety of techniques for converting various data formats to JSON files, JSON strings, etc. json.dumps(), which is used to convert any form of iterable to JSON, has also been covered in depth.

How Recursion Works In Prolog?

Introduction to Prolog Recursion

The prolog recursion is defined as, in prolog, the recursion seems when a predicate has some goal which referred to itself, the recursion is a function that can call itself until the goal succeeds, the predicates in prolog recursion are recursively defined because it has more than one rule in defining to refer itself, recursion is a powerful tool and it is widely used in prolog, it can also be used by many different data structures where the structures include sub-structures, it has two components one is base recursion and another is recursion itself, it mainly involves the predicates to calling itself, so prolog supports recursion.

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The syntax of recursion by using the family relationship:

predecessor(M,O) :- parent(M,N),predecessor(N,O).

So, the first line as the parent(M, O) has some facts given from there it will get instantiated, which is also called a base case, the second line shows the recursive relationship.

The clauses are divided into facts and rules.

Facts: The clauses without a body is called facts,

Syntax:

parent(M,O).

Which can be equivalent to-

parent(M,O):- true.

Rule: The rule is a type of form, it has been used to call the predicates and as we know the predicates are in-built in prolog.

For example, we have the clause that ‘Brain:- Heart.’, so it means ‘Brain is true if Heart is true’.

How Recursion Works in Prolog?

The recursion is a very powerful tool in prolog, recursion is used by many programming languages. So we wish to perform some operations either over data structure or until a certain point to be reached, in prolog this repetition is called recursion. It can also be used by many data structures so recursive data structure is the one where the structures include the sub-structures whose function is the same as that of the whole structure.

The predicate we are using in recursion is recursive in nature. We will see the working of recursion with the help of one example,

Example:

is_eating(S, T):- just_cook(S, T). is_eating(S, T):- just_cook(S, R),is_eating(R, T).

Let us see the working of recursion in family relationship, so we know that what is recursion, recursion is having mainly two issues, first is that for starting inputs and outputs are known to us so it is known as base case recursion, in prolog it will be satisfied by the given facts and another issue is that a prolog program or the prolog function can call itself, so we will see when the prolog calling itself in its declaration, so this can also a good example of recursion. So in other programming languages, we might have used recursion and prolog supports recursion and here in a family relationship, we can use recursion. As we have already defined parent, male, mother, father, haschild, brother, sister, grandparent, wife, and uncle family relationship and now we will see predecessor relationship. If P is the parent of Q then obviously P can be treated as a predecessor of Q, but if we go one step that means if P is the parent of Q and Q is the parent of R then we can say that P is the predecessor of R, similarly, if P is the parent of Q1 and Q1 is the parent of Q2 and Q2 is the parent of R then P can be called as the predecessor of R. In this way, we can move up to n number of levels.

predecessor(P,R):- parent(P,R). predecessor(P,R):- parent(P,Q),predecessor(Q,R).

In the above clauses we have declared predecessor(P, R) clause, we can demonstrate or say the above clause as the predecessor(P, R) if a parent(P, R) otherwise predecessor(P, R) if the parent(P, Q) and predecessor(Q, R), so in this way in predecessor declaration we use recursion. In the case of recursion, it has two issues one is that recursion has some base case where the algorithm gets terminate, the recursion algorithm must have a calling instruction itself either directly or indirectly. The predecessor(P, R) will be nothing but if P is one level higher than R then it will work otherwise we will go for multilevel higher. We are using predecessor on left and right both so that why it is a good example of recursion.

Example #1

Code:

:-initialization(main). main :- write('Recursion'). sumlist([], 0). sumlist(Item, SumOfItem), Sum is First + SumOfItem.

Input:

sumlist([4, 2, 3], Answer).

Output:

In the above program, we use recursive procedure ‘sumlist’, in every recursive call of ‘sumlist’ there is a separate instance of variables First, Item, Sum, SumofItem, and these are distinguished by a subscript, so it created First1 instance for First to call ‘sumlist’ and also First2 instance created for First in first recursive calling to call ‘sumlist’. We wrote a program to show the sum by putting the input which is given above.

Example #2

Code:

:- initialization(main). main :- write('fact and rule in recursion'). hat(beautiful). item(X) :- hat(X).

Input:

hat(beautiful).

hat(X).

Output:

In the above example, we explain the working of facts and rules in recursion by using prolog computer language. As prolog has an in-built predicate true/0 is always true. Hence to ask for given facts, we have given input as ‘hat(beautiful).’ it will give an output Yes. And when we give input ‘hat(X).’ then it will give the output with its value provided in code so it is ‘X=beautiful’ with yes, which is shown in the screenshot.

Conclusion

In the above article, we conclude that the prolog recursion is a technique to refer itself with some goal, it has declarative syntax with its rules, which has predecessor logic to show the relationship between family, we can also conclude that prolog is very comfortable with using recursive rules by using recursion we can easily find the ancestor.

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How Switch Works In Kotlin?

Introduction to Kotlin switch

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Syntax

In kotlin language have many default classes, methods, and other default variables used to implement the application in both UI and backend logic. The switch is one of the features and it is a loop case statement to iterate the values but now kotlin uses when keywords instead of switch.

{ val vars; when(vars) { —some logic and conditional statement codes—- } }

The above codes are the basic syntax for using the when keyword instead of switch blocks in the kotlin language. The looping and other conditional statements are evaluated and validated by the programmer.

How does Switch work in Kotlin?

The switch is one of the statements that can be used to declare and construct the loops to iterate the user input values. In kotlin language when a keyword can be used to declare the expression or statement while using that it can also satisfied with the branch’s value becoming the value of all the expressions. Each case statement is used with the individual branches the values are ignored and it is used with the default cases like java switch statement the else is the mandatory one when it used as the expression. If we used when keywords without any expressions it will act as the if-else chain blocks the boolean conditions and expressions also validated with specified logics. It is helpful when the user has n number of choices that want to be performed with the different tasks for each other choices. Mainly the switch statement allows for testing the variable in an equality manner against the list of values. Each value is defined and it is known as the cases generally the switch statement used break keyword for breaking the lines but is not a required manner it seems to be optional. Instead of switch when keyword used same case statements but here break keyword is not used and also we can use else statement if it is required.

Examples of Kotlin switch

Given below are the examples of Kotlin switch:

Example #1

Code:

package one; import java.util.* fun main() { var str1: String? = null var str2: String? = "Welcome To My Domain is the first example that relates to the Kotlin Switch statement" var strlen1: Int = if (str1 != null) str1.length else -1 var strlen2: Int = if (str2 != null) str2.length else -1 println("Length of str1 is ${strlen1}") println("Length of str2 is ${strlen2}") println("Enter the Color code from these jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec") val vars = readLine() val vars2 = when (vars) { } println("$vars2") println("Thank you users for spenting the time with our application") val sc = Scanner(System.`in`) print("Enter the numbers: ") val inp1 = sc.nextDouble() val inp2 = sc.nextDouble() val inp3 = sc.nextDouble() val inp4 = sc.nextDouble() val inp5 = sc.nextDouble() print("Please choose the operator to perform the mathematical operations (+, -, *, /): ") val opn = sc.next()[0] val out: Double when (opn) { System. out.printf("The operations are failed because due to the wrong inputs") return } } System.out.printf("%.1f %c %.1f = %.1f", inp1, opn, inp2, out) }

Sample Output:

In the above example, we calculate the mathematical operations by using the when statement.

Example #2

Code:

package one; import java.util.Scanner; fun demo(new: Any) = when (new) { } var str = Scanner(System.`in`) print("Please enter your brand:") var bndName = str.nextInt() var out = when(bndName){ println("Your brand is not listed here") } } println(out) var new = "Welcome To My Domain its the first example that relates to the Kotlin switch concept" var res = demo(new) if(res) { println("Yes, Your brand is listed Welcome To My Domain its the first example that relates to the Kotlin switch") } else { println("No, Sorry your brand is not listed here Kindly try with one more and please stay with our application and spent your valuable time for us thanks") } }

Sample Output:

In the second example we used to check the brand conditions with corresponding values with the help of the when statement.

Example #3 package one; import java.util.Scanner; enum class Textile { CHENNAISILKS, POTHYS, SRAVANASTORES, MJS, SPJ, SIVATEXTILE } fun main() { val result = Textile.POTHYS when (result) { } }

Sample Output:

In the final example, we used enum and we can create the reference of the enum and we called and iterate the enum values using the when statement.

Conclusion

In the kotlin language, we used many different concepts and features to implement the mobile with web-based applications. Like that the Switch is one of the looping and conditional expressions to validate the input data from both front and backend. We can use “when” keyword to achieve these switch case logics in the kotlin application.

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How List Function Works In Php

Introduction to PHP list

PHP list function is an important function used for assigning values to a list of variables while performing single operation at one go. This function is not present in all the PHP versions and is introduced exclusively in PHP versions before 7.1 which works only for numerical arrays while assigning values to the list of variables. The values assigned to the variables is the return type once executed with the help of PHP list function. PHP list function is not actually a function like array rather it is considered a language construct for assigning values.

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Syntax

list(var_1, var_2, ...)

The syntax flow is in a way where there is a list as function comprising of arguments passed from the function:

list: The function list() is declared.

var_1: The variable passed as an argument is required and is quite of mandatory in the sense this acts as the first variable to assign a value to the variable declared.

var_2: The second variable is optional and then this variable is used to assign values to the list followed by sequence.

This syntax when applied has a return type as assigned array which means whatever values are assigned to the array is the return type for that instance.

How list Function works in PHP?

list() function is an inbuild function in PHP which is exclusively used for assigning values to more than one variable by performing a single operation at the time of execution.

Let’s see the actual flow for working of list function in PHP which is described as follows :

Initially list being an inbuild function doesn’t required to be written and doesn’t require any external function call it works just seamlessly without much intrusion.

The array gets assigned with the required values from the multiple values considered at the time of execution.

There is a misconception regarding the array declared as a variable for assigning values but it’s just a myth in actual it is just a language construct.

Everything gets executed in a single operation using list() function while assigning variable.

This function works seamlessly on the numerical arrays only, which represents the fact that the user will get interacted with the arrays using first variable which is var_1.

The second argument getting passed to the function is an optional argument which gets retrieved and worked once the first argument satisfies the condition.

One point needs to be kept in mind which is like the number of variables should not exceed length of the numerical array and in case it exceeds the array defined variable then it will give error with parameters types and there will be no return type at the time of execution.

There should be no exception introduced while executing this list function otherwise the requirement and the return type will not get suffice.

If a function is not having any return statement, then implicitly it will return NULL as its return type at the time of execution.

The parameters to be passed as part of the function should be arranged in a way where the list of variables will get separated by spaces within the code.

The first variable to be passed from the function is a mandatory variable for the return type.

Another important point to look upon is the version compatibility which means that the PHP version should have version support less than 7.

Also, coming to the version compatibility for PHP then PHP version 5 in the list should assign values starting with right most parameter.

Whereas there is a difference with PHP version 7 where the assignment to the values of variable which will appear as left-most parameter.

In case normal variables are used then there is no need to worry about assigning values to the variables and then using these arrays with indices is used for arranging the values in an order.

But in case of order must be maintained like from left to right or from right to left then it is very much need to keep in mind about the PHP versioning.

Examples of PHP list

Given below are the examples of PHP list:

Example #1

This program demonstrates the PHP list where the array is assigned with the variable having values as shown in the output.

Code:

<?php $an_arr = array(“Banana”,”Mango”,”Apple”); list($a_1, $b_2, $c_3) = $an_arr; echo “I have many fruits, one $a_1, one $b_2 and one $c_3.”;

Output:

Example #2

This program demonstrates the PHP list where array is assigned with the first and third value within the variable as shown in the output.

Code:

<?php $arr_b = array(“Pencil”,”Copy”,”Pen”); list($k_0, , $z_1) = $arr_b; echo “Used_variable_for_modification $k_0 and $z_1 variables.”;

Output:

Example #3

This program demonstrates the declaration of array in a way where initially all the variables are listed, followed by retrieving some values and then listing some of them among all from which the third one gets skipped in case of the list with all the string it will return the NULL value as shown in the output.

Code:

<?php $in_p = array(‘choco’, ‘caramel’, ‘pancake’); list($choco, $cake, $caramel) = $in_p; echo “$choco cake $color and $caramel appears relishing n”; list( , , $caramel) = $in_p; echo “caramel cake tastes wow $caramel!n”; list($choco, , $cake) = $in_p; echo “$choco has $cake.n”; list($gi_t) = “lost_in n”; list($choco, , $cake) = $in_p; echo “$choco has $cake.n”; var_dump($gi_t);

Example #4

This program demonstrates the nested array by using list function as shown in the output.

Code:

<?php list($a_1, list($b_2, $c_0)) = array(1, array(4, 6)); var_dump($a_1, $b_2, $c_0); echo “listing of nested array”;

Output:

Conclusion

PHP list is an inbuild function which gives user the flexibility and versatility to adapt this function as part of the implementation as per requirement. Use of PHP list make the values arranged in some order which gives user visibility to implement a user-friendly array return values with variables.

Recommended Articles

This is a guide to PHP list. Here we discuss the introduction, how list function works in PHP? along with examples respectively. You may also have a look at the following articles to learn more –

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