Minimal Error Example

Given the following minimal example where you create a set and attempt to access an element of this set using indexing or slicing:

my_set = {1, 2, 3}

my_set[0]

If you run this code snippet, Python raises the TypeError: 'set' object is not subscriptable:

Traceback (most recent call last): File "C:\Users\xcent\Desktop\code.py", line 2, in <module> my_set[0]

TypeError: 'set' object is not subscriptable

Why Does the Error Occur?

The Python TypeError: 'set' object is not subscriptable occurs if you try to access an element of a set using indexing or slicing that imply an ordering of the set.

However, sets are unordered collections of unique elements: they have no ordering of elements. Thus, you cannot use slicing or indexing, operations that are only possible on an ordered type.

Recommended Tutorial: The Ultimate Guide to Python Sets

How to Fix the Error?

How to fix the TypeError: 'set' object is not subscriptable?

To fix the TypeError: 'set' object is not subscriptable, either convert the unordered set to an ordered list or tuple before accessing it or get rid of the indexing or slicing call altogether.

Here’s an example where you convert the unordered set to an ordered list first. Only then you use indexing or slicing so the error doesn’t occur anymore:

my_set = {1, 2, 3} # Convert set to list:

my_list = list(my_set) # Indexing:

print(my_list[0])

# 1 # Slicing:

print(my_list[:-1])

# [1, 2]

Alternatively, you can also convert the set to a tuple to avoid the TypeError: 'set' object is not subscriptable:

my_tuple = tuple(my_set)

Let’s end this article with a bit of humor, shall we?

Programmer Humor

There are only 10 kinds of people in this world: those who know binary and those who don’t.

~~~

There are 10 types of people in the world. Those who understand trinary, those who don’t, and those who mistake it for binary.

Given an image as a .png or .jpeg file. How to convert it to a CSV file in Python?

Example image:

Convert the image to a CSV using the following steps:

1. Read the image into a PIL.Image object.
2. Convert the PIL.Image object to a 3D NumPy array with the dimensions rows, columns, and RGB values.
3. Convert the 3D NumPy array to a 2D list of lists by collapsing the RGB values into a single value (e.g., a string representation).
4. Write the 2D list of lists to a CSV using normal file I/O in Python.

Here’s the code that applies these four steps, assuming the image is stored in a file named 'c++.jpg':

from PIL import Image

import numpy as np # 1. Read image

img = Image.open('c++.jpg') # 2. Convert image to NumPy array

arr = np.asarray(img)

print(arr.shape)

# (771, 771, 3) # 3. Convert 3D array to 2D list of lists

lst = []

for row in arr: tmp = [] for col in row: tmp.append(str(col)) lst.append(tmp) # 4. Save list of lists to CSV

with open('my_file.csv', 'w') as f: for row in lst: f.write(','.join(row) + '\n')

Note that the resulting CSV file looks like this with super long rows.

Each CSV cell (column) value is a representation of the RGB value at that specific pixel. For example, [255 255 255] represents the color white at that pixel.

For more information and some background on file I/O, check out our detailed tutorial on converting a list of lists to a CSV:

Related Tutorial: How to Convert a List to a CSV File in Python [5 Ways]

This example script in JavaScript is to copy text to the system clipboard. I am presenting three different methods in this tutorial.

1. Via ClipBoard API.
2. Using document.executeCommand (not recommended).
3. By user consent.

This JS quick example uses the first and the best method to copy content of a textarea to the clipboard.

var contentToCopy = document.getElementById(text_to_copy).value;

navigator.clipboard.writeText(contentToCopy).then(function() { console.log('Copied to clipboard with async.');

}, function(err) { console.error('Unable to copy with async ', err);

});

HTML textarea element from where the content is copied by the JS script.

<textarea id="text_to_copy">Text to copy</textarea>

1) Using The Clipboard API

Below HTML script gives an interface with a textarea and a button to trigger the copy action.

On clicking the button to call the JavaScript copyToClipBoard() function. This function moves the textarea content to the clipboard.

index.html

<html>

<head>

<title>JavaScript Copy Text to Clipboard</title>

<script src="copy-clipboard-async.js"></script>

<script src="https://code.jquery.com/jquery-3.6.1.min.js" integrity="sha256-o88AwQnZB+VDvE9tvIXrMQaPlFFSUTR+nldQm1LuPXQ=" crossorigin="anonymous"></script>

<link rel='stylesheet' href='style.css' type='text/css' />

<link rel='stylesheet' href='form.css' type='text/css' />

</head>

<body> <div class="phppot-container"> <h1>JavaScript Copy Text to Clipboard</h1> <div class="row"> <div class="message-input"> <label for="message-input">Message: </label> <textarea id="message-input" rows="15" name="message-input" class="message-input"></textarea> </div> </div> <div class="row"> <button on‌click="copyToClipboard('message-input')" type="button">Copy to clipboard</button> </div> <div class="row"> <div id="copied"></div> </div> </div>

</body>

</html>

This JS script writes the text to the clipboard by calling clipboard.writeText(). It enhances the quick example by providing an interface to copy content via ClipBoard API.

copy-clipboard-async.js

/** * to copy to the clipboard using the Clipboard API * * @param element * @returns */

function copyToClipboard(element) { var contentToCopy = document.getElementById(element).value; navigator.clipboard.writeText(contentToCopy).then(function() { console.log('Copied to clipboard with async.'); }, function(err) { console.error('Unable to copy with async ', err); });

}

2) document.execCommand

This method was widely used to copy content by calling the executeCommand(“copy”). It is deprecated but still supported by many browsers.

It dynamically appends the textarea element to the HTML body and selects its content using JavaScript. Then the executeCommand() function call triggers the copy action.

copy-clipboard-execcommand.js

/** * to copy to the clipboard using the document.execCommand * * @param element * @returns */

function copyToClipboard(element) { var contentToCopy = document.getElementById(element).value; var temp = $("<textarea>"); $("body").append($temp); temp.val(contentToCopy); temp.select(); document.execCommand("copy"); temp.remove(); console.log('Copied!');

}

3) Copy by user

This is the safest method of copying the content to the clipboard. This does not use any native function of the JavaScript and can be described more of a process. It prompts the user to confirm copying the selected content to the clipboard.

copy-by-user-consent.html

<html>

<head>

<title>JavaScript Copy Text to Clipboard</title>

</head>

<body> <!-- In this style, we present the control to the end user to copy. --> <!-- Text to be copied is shown to the user and he uses the built-in browser's feature and copies to the clipboard. --> <!-- If this is possible to use in your use case, then this is the safest method. --> <button id="copy-btn" on‌click="copyToClipboard(document.getElementById('copy-btn').innerHTML)">Text to copy.</button> <script> function copyToClipboard(text) { window.prompt("Press Ctrl+C to copy to clipboard.", text); } </script>

</body>

</html>

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