JSON is the best format to transfer data over network. It is an easily parsable format comparatively. That’s why most of the API accepts parameters and returns responses in JSON.

There are online tools to convert an array to a JSON object. This tutorial teaches how to create a program to convert various types of PHP array input into a JSON format.

It has 4 different examples for converting a PHP array to JSON. Those are too tiny in purpose to let beginners understand this concept easily.

Quick example

This quick example is simply coded with a three-line straightforward solution. It takes a single-dimensional PHP array and converts it to JSON.

<?php

$array = array(100, 250, 375, 400);

$jsonString = json_encode($array);

echo $jsonString;

?>

View Demo

The other different array-to-JSON examples handle simple to complex array conversion. It also applies pre-modification (like array mapping) before conversion. The four examples are,

1. Simple to complex PHP array to JSON.
2. Remove array keys before converting to JSON.
3. Convert PHP array with accented characters to JSON
4. PHP Array to JSON with pretty-printing

If you want the code for the reverse to decode JSON objects to an array, then the linked article has examples.

See this online demo to convert an array of comma-separated values into a JSON object.

1) Simple to complex PHP array to JSON

This code handles 3 types of array data into a JSON object. In PHP, it is very easy to convert an array to JSON.

It is a one-line code by using the PHP json_encode() function.

<?php

// PHP Array to JSON string conversion for

// simple, associative and multidimensional arrays

// all works the same way using json_encode

// just present different arrays for example purposes only // simple PHP Array to JSON string

echo '<h1>PHP Array to JSON</h1>';

$array = array( 100, 250, 375, 400

);

$jsonString = json_encode($array);

echo $jsonString; // Associative Array to JSON

echo '<h2>Associative PHP Array to JSON</h2>';

$array = array( 'e1' => 1000, 'e2' => 1500, 'e3' => 2000, 'e4' => 2350, 'e5' => 3000

);

$jsonString = json_encode($array);

echo $jsonString; // multidimensional PHP Array to JSON string

echo '<h2>Multidimensional PHP Array to JSON</h2>';

$multiArray = array( 'a1' => array( 'item_id' => 1, 'name' => 'Lion', 'type' => 'Wild', 'location' => 'Zoo' ), 'a2' => array( 'item_id' => 2, 'name' => 'Cat', 'type' => 'Domestic', 'location' => 'Home' )

);

echo json_encode($multiArray);

?>

Output:

//PHP Array to JSON
[100,250,375,400] //Associative PHP Array to JSON
{"e1":1000,"e2":1500,"e3":2000,"e4":2350,"e5":3000} //Multidimensional PHP Array to JSON
{"a1":{"item_id":1,"name":"Lion","type":"Wild","location":"Zoo"},"a2":{"item_id":2,"name":"Cat","type":"Domestic","location":"Home"}}

2) Remove array keys before converting to JSON

This code handles a different scenario of JSON conversion which must be helpful if needed. For example, if the array associates subject=>marks and the user needs only the marks to plot it in a graph.

It removes the user-defined keys from an associative array and applies json_encode to convert it. It is a two-step process.

1. It applies PHP array_values() to read the value array.
2. Then, it applies json_encode on the values array.

<?php

// array_values() to remove assigned keys and convert to the original PHP Array key

echo '<h1>To remove assigned associative keys and PHP Array to JSON</h1>';

$array = array( 'e1' => 1000, 'e2' => 1500, 'e3' => 2000, 'e4' => 2350, 'e5' => 3000

); $jsonString = json_encode(array_values($array));

echo $jsonString;

?>

Output:

[1000,1500,2000,2350,3000]

3) Convert the PHP array with accented characters to JSON

It is also a two-step process to convert the array of data containing accented characters.

It applies UTF8 encoding on the array values before converting them into a JSON object.

For encoding all the elements of the given array, it maps the utf8_encode() as a callback using the PHP array_map() function.

We have seen PHP array functions that are frequently used while working with arrays.

<?php

// Accented characters

// to preserve accented characters during PHP Array to JSON conversion

// you need to utf8 encode the values and then do json_encode

echo '<h1>For accented characters PHP Array to JSON</h1>';

$array = array( 'w1' => 'résumé', 'w2' => 'château', 'w3' => 'façade', 'w4' => 'déjà vu', 'w5' => 'São Paulo'

);

$utfEncodedArray = array_map("utf8_encode", $array);

echo json_encode($utfEncodedArray);

?>

Output:

{"w1":"r\u00c3\u00a9sum\u00c3\u00a9","w2":"ch\u00c3\u00a2teau","w3":"fa\u00c3\u00a7ade","w4":"d\u00c3\u00a9j\u00c3\u00a0 vu","w5":"S\u00c3\u00a3o Paulo"}

4) PHP Array to JSON with pretty-printing

It applies to prettyprint on the converted output JSON properties in a neet spacious format.

The PHP json_encode() function accepts the second parameter to set the bitmask flag. This flag is used to set the JSON_PRETTY_PRINT to align the output JSON properties.

<?php

// to neatly align the output with spaces

// it may be useful when you plan to print the

// JSON output in a raw format

// helpful when debugging complex multidimensional PHP Arrays and JSON objects

// lot more constants are available like this, which might be handy in situations

echo '<h1>Convert PHP Array to JSON and Pretty Print</h1>';

$array = array( 'e1' => 1000, 'e2' => 1500, 'e3' => 2000, 'e4' => 2350, 'e5' => 3000

);

echo json_encode($array, JSON_PRETTY_PRINT);

?>

Output:

{ "e1": 1000, "e2": 1500, "e3": 2000, "e4": 2350, "e5": 3000 }

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Summary: Use the list("given string") to extract each character of the given string and store them as individual items in a list.
Minimal Example:
print(list("abc"))

Problem: Given a string; How will you split the string into a list of characters?

Example: Let’s visualize the problem with the help of an example:

Now that we have an overview of our problem let us dive into the solutions without further ado.

Method 1: Using The list Constructor

Approach: One of the simplest ways to solve the given problem is to use the list constructor and pass the given string into it as the input.

list() creates a new list object that contains items obtained by iterating over the input iterable. Since a string is an iterable formed by combining a group of characters, hence, iterating over it using the list constructor yields a single character at each iteration which represents individual items in the newly formed list.

Code:

text = "finxter"

print(list(text)) # ['f', 'i', 'n', 'x', 't', 'e', 'r']

Related Tutorial: Python list() — A Simple Guide with Video

Method 2: Using a List Comprehension

Another way to split the given string into characters would be to use a list comprehension such that the list comprehension returns a new list containing each character of the given string as individual items.

Code:

text = "finxter"

print([x for x in text]) # ['f', 'i', 'n', 'x', 't', 'e', 'r']

Prerequisite: To understand what happened in the above code, it is essential to know what a list comprehension does. In simple words, a list comprehension in Python is a compact way of creating lists. The simple formula is [expression + context], where the “expression” determines what to do with each list element. And the “context” determines what elements to select. The context can consist of an arbitrary number of for and if statements. To learn more about list comprehensions, head on to this detailed guide on list comprehensions.

Explanation: Well! Now that you know what list comprehensions are, let’s try to understand what the above code does. In our solution, the context variable x is used to extract each character from the given string by iterating across each character of the string one by one with the help of a for loop. This context variable x also happens to be the expression of our list comprehension as it stores the individual characters of the given string as separate items in the newly formed list.

Multi-line Solution: Another approach to formulating the above solution is to use a for loop. The idea is pretty similar; however, we will not be using a list comprehension in this case. Instead, we will use a for loop to iterate across individual characters of the given string and store them one by one in a new list with the help of the append method.

text = "finxter"

res = []

for i in text: res.append(i)

print(res) # ['f', 'i', 'n', 'x', 't', 'e', 'r']

Method 3: Using map and lambda

Yet another way of solving the given problem is to use a lambda function within the map function. Now, this is complex and certainly not the best fit solution to the given problem. However, it may (or may not ;P) be appropriate when you are handling really complex tasks. So, here’s how to use the two built-in Python functions to solve the given problem:

import re

text = "finxter"

print(list(map(lambda c: c, text))) # ['f', 'i', 'n', 'x', 't', 'e', 'r']

Explanation: The map() function is used to execute a specified function for each item of an iterable. In this case, the iterable is the given string and each character of the string represents an individual item within it. Now, all we need to do is to create a lambda function that simply returns the character passed to it as the input. That’s it! However, the map method will return a map object, so you must convert it to a list using the list() function. Silly! Isn’t it? Nevertheless, it works!

Conclusion

Hurrah! We have successfully solved the given problem using as many as three different ways. I hope you enjoyed this article and it helps you in your Python coding journey. Please subscribe and stay tuned for more interesting articles!

Related Reads:
⦿ How To Split A String And Keep The Separators?
⦿ How To Cut A String In Python?

Do you need to create a function that returns a file but you don’t know how? No worries, in sixty seconds, you’ll know! Go!

A Python function can return any object such as a file object. To return a file, first open the file object within the function body, handle all possible errors if the file doesn’t exist, and return it to the caller of the function using the keyword operation return open(filename, mode='r').

Here’s a minimal example that tries to open a filename that was provided by the user via the input() function. If it fails, it prints an error message and asks for a different user input:

def open_file(): while True: filename = input('filename: ') try: return open(filename, mode='r') except: print('Error. Try again') f = open_file()

print(f.read()) 

If I type in the correct file right away, I get the following output when storing the previous code snippet in a file named code.py—the code reads itself (meta ):

filename: code.py

def open_file(): while True: filename = input('filename: ') try: return open(filename, mode='r') except: print('Error. Try again') f = open_file()

print(f.read())

Note that you can open the file in writing mode rather than reading mode by replacing the line with the return statement with the following line:

open(filename, mode='w')

A more Pythonic way, in my opinion, is to follow the single-responsibility pattern whereby a function should do only one thing. In that case, provide the relevant input values into the function like so:

def open_file(filename, mode): try: return open(filename, mode=mode) except: return None def ask_user(): f = open_file(input('filename: '), input('mode: ')) while not f: f = open_file(input('filename: '), input('mode: ')) return f f = ask_user() print(f.read()) 

Notice how the file handling of a single instance and the user input processing are separated into two functions. Each function does one thing only. Unix style.

If you want to improve your programming skills and coding productivity creating massive success with your apps and coding projects, feel free to check out my book on the topic:

The Art of Clean Code

Most software developers waste thousands of hours working with overly complex code. The eight core principles in The Art of Clean Coding will teach you how to write clear, maintainable code without compromising functionality. The book’s guiding principle is simplicity: reduce and simplify, then reinvest energy in the important parts to save you countless hours and ease the often onerous task of code maintenance.

1. Concentrate on the important stuff with the 80/20 principle — focus on the 20% of your code that matters most
2. Avoid coding in isolation: create a minimum viable product to get early feedback
3. Write code cleanly and simply to eliminate clutter
4. Avoid premature optimization that risks over-complicating code
5. Balance your goals, capacity, and feedback to achieve the productive state of Flow
6. Apply the Do One Thing Well philosophy to vastly improve functionality
7. Design efficient user interfaces with the Less is More principle
8. Tie your new skills together into one unifying principle: Focus

The Python-based The Art of Clean Coding is suitable for programmers at any level, with ideas presented in a language-agnostic manner.

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Programmer Humor

Q: How do you tell an introverted computer scientist from an extroverted computer scientist? A: An extroverted computer scientist looks at your shoes when he talks to you.