Summary: You can split a given string at a specific position/index using Python’s string–slicing syntax.

Minimal Example:

# Method 1:

s = "split string at position"

print(s[:12])

print(s[13:]) # Method 2:

import re

s = "split string at position"

pos = re.search('at', s)

l = s[:pos.start()]

r = s[pos.start():]

print(l)

print® # OUTPUT:

split string

at position

Problem Formulation

Problem: Given a string, how will you split the given string at any given position?

Let’s have a look at a couple of examples that demonstrate what the problem asks you to do:

◈Example 1

The following problem requires us to split the string into two parts. You have to cut the given string into two halves based on a certain index/position. The given cut position/index is 12.

# Input

s = "split string at position"

# Output

split string

at position

◈Example 2

The following problem asks us to split the string based on the position of a certain character (“,”) and a word (“or”) present in the string. Thus, in this case, you have not been given the exact position or index to split the string. Instead, you have to find the index/position of certain characters and then split the string accordingly based on the positions of the given characters and words and store the required sub-strings in different variables.

# Input

text = "Bob is the Relationship Manager, contact him at bob@xyz.abc or call him at 6546 "

# Output:

Personnel: Bob is the Relationship Manager

Email: contact him at bob@xyz.abc

Contact Info: call him at 6546

Now, let’s dive into the different ways of solving this problem.

Method 1: Using String Slicing

String slicing is the concept of carving a substring from a given string. Use slicing notation s[start :stop: step] to access every step-th element starting from index start (included) and ending in index stop (excluded). All three arguments are optional, so you can skip them to use the default values (start = 0, stop = len(string), step = 1.)

Related Tutorial: String Slicing in Python.

◈Example 1 Solution

Approach: Use string slicing to cut the given string at the required position. To do this, you have to use the square-bracket syntax within which you can specify the starting and ending indices to carve out the required sub-strings as shown in the solution below.

Code:

s = "split string at position"

print(s[:12])

print(s[13:])

Output:

split string

at position

◈Example 2 Solution

Approach: Use the index() method of the given character, i.e., “,” and the substring “or” within the given string. Then use this index to extract the required chunks of substrings by splitting the given string with the help of string slicing.

Code:

text = "Bob is the Relationship Manager, contact him at bob@xyz.abc or call him at 6546 "

# get the position of characters where you want to split the string

pos_comma = text.index(',')

pos_or = text.index('or')

# Slice the string based on the position of comma

personnel, email, phone = text[:pos_comma], text[pos_comma+1:pos_or], text[pos_or+2:]

print(f'Personnel: {personnel}\nEmail: {email}\nContact Info: {phone}')

Output:

Personnel: Bob is the Relationship Manager

Email: contact him at bob@xyz.abc Contact Info: call him at 6546 

Note: The index() method allows you to find the index of the first occurrence of a substring within a given string. You can learn more about Python’s index() method here: Python String index().

◈Method 2: Using regex

If a regular expression matches a part of your string, a lot of helpful information comes with it, for example, you can find out what’s the exact position of the match. The re.search(pattern, string) method is used to match the first occurrence of a specified pattern in the string and returns a match object. Thus, you can use it to solve the given problem.

Related read: Python Regex Search

Pre-requisite: match_object.start() is a method used to get the position of the first character of the match object and match_object.end() is the method to get the last character of the match object.

A Quick Look at The Official Documentation:

◈Example 1 Solution

Approach:

• Import the regex module and then create a match object by using the re.search() method. You can do this by passing the substring/character that lies at the given split index/position. In this case, the substring that lies at the split index is “at“.
• We can then split the string by accessing the start position of the matched string object by calling the method pos.start() where pos denotes the matched object.
• Then to get the first half of the split string, you can use string slicing as s[:pos.start()]. Here, we sliced the original string from the start index of the given string until the index of the searched character (not included) that was extracted in the previous step.
• Further, we need the second section of the split string. Thus, we will now slice the original string from the index of the searched character to the end of the string, like so: s[pos.start():]

Code:

import re s = "split string at position"

pos = re.search('at', s)

l = s[:pos.start()]

r = s[pos.start():]

print(l)

print®

Output:

split string

at position

◈Example 2 Solution

The idea is pretty similar to the solution of example 1. You just need to adjust the start and stop indices within the slice syntax with the help of the start() and end() methods to extract the required split sub-strings one by one.

Code:

import re

text = "Bob is the Relationship Manager, contact him at bob@xyz.abc or call him at 6546"

# Look for the match objects

_comma = re.search(',', text)

_or = re.search('or', text)

# slice to get first substring

personnel = text[:_comma.start()]

# slice to get second substring

email = text[_comma.end()+1:_or.start()]

# slice to get third substring

phone = text[_or.end():]

# Final Output

print(f'Personnel: {personnel}\nEmail: {email}\nContact Info: {phone}')

Output:

Personnel: Bob is the Relationship Manager

Email: contact him at bob@xyz.abc or

Contact Info: call him at 6546

Conclusion

Woohoo! We have successfully solved splitting a string at the position using two different ways. I hope you enjoyed this article and it helps you in your coding journey. Please subscribe and stay tuned for more such interesting articles!

Related Reads:
⦿ Python | Split String by Whitespace
⦿ How To Cut A String In Python?
⦿ Python | Split String into Characters

Google, Facebook, and Amazon engineers are regular expression masters. If you want to become one as well, check out our new book: The Smartest Way to Learn Python Regex (Amazon Kindle/Print, opens in new tab).

This tutorial covers the basic details of the PHP json_encode function. It gives examples of decoding JSON string input to a PHP array.

It also describes this PHP JSON function‘s conventions, rules and limitations. First, let’s see a quick example of converting JSON to an array.

Convert JSON to PHP Array

This example has a JSON string that maps the animal with its count. The output of converting this JSON will return an associative array.

It uses PHP json_decode() with boolean true as its second parameter. With these decoding params, the JSON will be converted into a PHP array.

<?php

// JSON string in PHP Array

$jsonString = '{"Lion":101,"Tiger":102,"Crocodile":103,"Elephant":104}';

$phpArray = json_decode($jsonString, true); // display the converted PHP array

var_dump($phpArray);

?>

Output

array(4) { ["Lion"]=> int(101) ["Tiger"]=> int(102) ["Crocodile"]=> int(103) ["Elephant"]=> int(104)
}

See this online demo to get the converted array result from a JSON input.
View demo

See the diagram that shows the input JSON string and the output stdClass object of the JSON decoding. In the previous article, we have seen examples of the reverse operation that is converting a PHP array to a JSON string.

PHP json_decode()

This native PHP function decodes the JSON string into a parsable object tree or an array. This is the syntax of this function.

json_decode( string $json, ?bool $associative = null, int $depth = 512, int $flags = 0

): mixed

1. $json – Input JSON string.
2. $associative – a boolean based on which the output format varies between an associative array and a stdClass object.
3. $depth – the allowed nesting limit.
4. $flag – Predefine constants to enable features like exception handling during the JSON to array convert.

You can find more about this function in the official documentation online.

Convert JSON to PHP Object

This program has a minute change of not setting the boolean flag to the PHP json_decode function. This will return a PHP stdClass object tree instead of an array.

<?php

// JSON string in PHP Array

$jsonString = '{"name":"Lion"}'; $phpObject = json_decode($jsonString);

print $phpObject->name;

?>

Output

Lion

Common mistakes during conversion from JSON to Array

The following JSON string is a valid JSON object in JavaScript, but not here in PHP. The issue is the single quote. It should be changed to a double quote.

If you want to see the JavaScript example to read and display JSON data the linked article has the code.

<?php

// 1. key and value should be within double quotes

$notValidJson = "{ 'lion': 'animal' }";

json_decode($notValidJson); // will return null // 2. without a quote is also not allowed

$notValidJson = '{ lion: "animal" }';

json_decode($notValidJson); // will return null // 3. should not have a comma at the end

$notValidJson = '{ "lion": "animal", }';

json_decode($notValidJson); // will return null

?>

How to convert JSON with large integers

This can be achieved by setting the bitmask parameter of the predefined JSON constants.

The JSON_BIGINT_AS_STRING constant is used to convert JSON with data having large integers.

<?php

$jsonString = '{"largeNumber": 12345678901234567890123}'; var_dump(json_decode($jsonString, false, 512, JSON_BIGINT_AS_STRING));

?>

Output

object(stdClass)#1 (1) { ["number"]=> string(20) "12345678901234567890123"
}

How to get errors when using json_decode

The function json_last_error() is used to return details about the last error occurrence. The following example handles the possible error cases of this PHP JSON function.

<?php

$jsonString = '{"Lion":101,"Tiger":102,"Crocodile":103,"Elephant":104}';

json_decode($jsonString); switch (json_last_error()) { case JSON_ERROR_DEPTH: echo 'Error: Nesting limit exceeded.'; break; case JSON_ERROR_STATE_MISMATCH: echo 'Error: Modes mismatch.'; break; case JSON_ERROR_CTRL_CHAR: echo 'Error: Unexpected character found.'; break; case JSON_ERROR_SYNTAX: echo 'Error: Syntax error, invalid JSON.'; break; case JSON_ERROR_UTF8: echo 'Error: UTF-8 characters incorrect encoding.'; break; default: echo 'Unexpected error.'; break;

}

?>

SURPRISE! JSON to Array and Array to JSON conversion is not symmetrical

<?php $jsonString = '{"0": "No", "1": "Yes"}'; // convert json to an associative array $array = json_decode($jsonString, true); print json_encode($array) . PHP_EOL;

?>

Output

["No","Yes"]

The PHP object is now changed to a PHP array. You may not expect it.

Encode -> Decode -> Encode

The above will not return the data to its original form.

The output of decoding to PHP arrays and encoding from PHP arrays are not always symmetrical. But, the output of decoding from stdClass objects and encoding to stdClass objects are always symmetrical.

So if you have plans to do cyclical conversion between the PHP array and a JSON string, then first convert the PHP array to an object. The convert the JSON.

View demo

↑ Back to Top

Problem Formulation and Solution Overview

This article will show you how 6 ways to remove List elements in Python.

To make it more interesting, we have the following running scenario:

Suppose you have a Christmas List containing everyone to buy a gift for. Once a gift is purchased, remove this person from the List. Once all gifts have been purchased, remove the entire List.

Question: How would we write code to remove items from a Python List?

We can accomplish this task by one of the following options:

• Method 1: Use the del Keyword
• Method 2: Use remove() and a for Loop
• Method 3: Use slicing
• Method 4: Use pop()
• Method 5: Use List Comprehension
• Method 6: Use clear()

Method 1: Use the del Keyword

This method uses Python’s del Keyword and highlights its ability to remove one List element and all List elements.

Remove One List Element

In this scenario, Asa's gift has been purchased and will be removed from the List.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

del xmas_list[3]

print(xmas_list)

As shown on the highlighted line, Asa is removed from the List by using del, referencing xmas_list and specifying Asa’s location ([3]).

When xmas_list is output to the terminal, the following displays.

Remove All List Elements

In this scenario, all gifts have been purchased, and all List elements will be removed.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

del xmas_list

print(xmas_list)

As shown on the highlighted line, all elements of xmas_list are removed by using del and referencing xmas_list.

When xmas_list is output to the terminal, the following error is generated.

Note: This error is generated because the variable xmas_list no longer exists in memory.

Method 2: Use remove() and a For Loop

This example uses the remove() function in conjunction with a for loop to remove one List element and all List elements.

Remove One List Element

In this scenario, Elin's gift has been purchased and will be removed from the List.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list.remove('Elin')

print(xmas_list)

As shown on the highlighted line, Elin is removed from the List using the remove() function and passing Elin’s name as an argument.

When xmas_list is output to the terminal, the following displays.

Remove All List Elements

In this scenario, all gifts have been purchased, and all List elements will be removed.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

for item in xmas_list.copy(): xmas_list.remove(item)

print(xmas_list)

As shown on the first highlighted line, a for loop is instantiated. This loop declares a shallow copy of the List to iterate.

On each iteration, the remove() function is called and passed the current name in xmas_list as an argument (see below) and removed.

For example:

When xmas_list is output to the terminal, an empty List displays.

Note: A shallow copy creates a reference to the original List. For further details, view the video below.

Method 3: Use slicing

This method uses slicing to remove one List element and all List elements.

Remove One List Element

In this scenario, Anna's gift has been purchased and will be removed from the List.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list = xmas_list[1:]

print(xmas_list)

As shown on the highlighted line, Anna is removed from the List using slicing.

When xmas_list is output to the terminal, the following displays.

Remove All List Elements

In this scenario, all gifts have been purchased, and all List elements will be removed.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list = []

print(xmas_list)

As shown on the highlighted line, all List elements are removed by declaring an empty List.

When xmas_list is output to the terminal, an empty List displays.

Method 4: Use pop()

This method uses the pop() function to remove one List element and all List elements.

Remove One List Element

In this scenario, Linn's gift has been purchased and will be removed from the List.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list.pop()

xmas_list.pop(2)

print(xmas_list)

As shown on the first highlighted line, the pop() method is appended to the xmas_list. This lets Python know to remove a List element from said List. Since no element is specified, the last element is removed (Linn).

On the second highlighted line, the pop() method is appended to the xmas_list and passed one (1) argument: the element to remove (2). This action removes Inger.

When xmas_list is output to the terminal, the following displays.

Note: Both Linn and Inger are no longer in xmas_list.

Remove All List Elements

In this scenario, all gifts have been purchased, and all List elements will be removed.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn'] for i in xmas_list.copy(): xmas_list.pop()

print(xmas_list)

As shown on the first highlighted line, a for loop is instantiated. This loop declares a shallow copy of the List to iterate.

On each iteration, the pop() method is called. Since no argument is passed, the last element is removed.

When xmas_list is output to the terminal, an empty List displays.

Method 5: Use List Comprehension

This method uses List Comprehension to remove all List elements that do not meet the specified criteria.

Remove One List Element

In this scenario, Gunnel's gift has been purchased and will be removed from the List.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list = [value for value in xmas_list if value != 'Gunnel']

print(xmas_list)

When xmas_list is output to the terminal, the following displays.

Note: To remove all List elements, pass it empty brackets as shown follows: (xmas_list = []).

Method 6: Use clear()

This method uses clear() to remove all List elements.

In this scenario, all gifts have been purchased, and all List elements will be removed.

xmas_list = ['Anna', 'Elin', 'Inger', 'Asa', 'Sofie', 'Gunnel', 'Linn']

xmas_list.clear()

print(xmas_list)

As shown on the highlighted line, all List elements are removed by appending the clear() function to xmas_list.

When xmas_list is output to the terminal, an empty List displays.

Summary

This article has provided six (6) ways to remove List elements to select the best fit for your coding requirements.

Good Luck & Happy Coding!

Programming Humor

Programming is 10% science, 20% ingenuity, and 70% getting the ingenuity to work with the science.

~~~

• Question: Why do Java programmers wear glasses?
• Answer: Because they cannot C# …!

Feel free to check out our blog article with more coding jokes.