Our first DevNation Live regional event was held in Bengaluru, India in July. This free technology event focused on open source innovations, with sessions presented by elite Red Hat technologists.

Quarkus is revolutionizing the way that we develop Java applications for the cloud-native era, and in this presentation, Edson Yanaga explains why it also sparks joy.

Watch this live coding session to get familiar with Quarkus and learn how your old and new favorite APIs will start in a matter of milliseconds and consume tiny amounts of memory. Hot reload capabilities for development will bring you instant joy.

Watch the complete presentation:

See the slides here.

Learn more

Join us at an upcoming developer event, and see our collection of past DevNation Live tech talks.

The post Bring joy to development with Quarkus, the cloud-native Java framework appeared first on Red Hat Developer.

Python’s built-in dict() function creates and returns a new dictionary object from the comma-separated argument list of key = value mappings. For example, dict(name = 'Alice', age = 22, profession = 'programmer') creates a dictionary with three mappings: {'name': 'Alice', 'age': 22, 'profession': 'programmer'}. A dictionary is an unordered and mutable data structure, so it can be changed after creation.

Read more about dictionaries in our full tutorial about Python Dictionaries.

Usage

Learn by example! Here are some examples of how to use the dict() built-in function:

>>> dict(name = 'Alice')

{'name': 'Alice'}

>>> dict(name = 'Alice', age = 22)

{'name': 'Alice', 'age': 22}

>>> dict(name = 'Alice', age = 22, profession = 'programmer')

{'name': 'Alice', 'age': 22, 'profession': 'programmer'}

You can pass an arbitrary number of those comma-separated key = value pairs into the dict() constructor.

Video dict()

Syntax dict()

You can use the dict() method with an arbitrary number of key=value arguments, comma-separated.

Syntax: There are four ways of using the constructor:

dict() -> new empty dictionary dict(mapping) -> new dictionary initialized from a mapping object's (key, value) pairs
dict(iterable) -> new dictionary initialized from an iterable of (key, value) tuples
dict(**kwargs) -> new dictionary initialized with the name=value pairs in the keyword argument list.

Interactive Shell Exercise: Understanding dict()

Consider the following interactive code:

Exercise: Guess the output before running the code.

---

But before we move on, I’m excited to present you my brand-new Python book Python One-Liners (Amazon Link).

If you like one-liners, you’ll LOVE the book. It’ll teach you everything there is to know about a single line of Python code. But it’s also an introduction to computer science, data science, machine learning, and algorithms. The universe in a single line of Python!

The book is released in 2020 with the world-class programming book publisher NoStarch Press (San Francisco).

Link: https://nostarch.com/pythononeliners

---

The dict() function has many different options to be called with different types of arguments. You’ll learn different ways to use the dict() function next.

How to Create an Empty Dictionary?

You can create an empty dictionary by using Python’s built-in dict() function without any argument. This returns an empty dictionary. As the dictionary is a mutable data structure, you can add more mappings later by using the d[key] = value syntax.

>>> d = dict()

>>> d['Alice'] = 22

>>> d

{'Alice': 22}

How to Create a Dictionary Using Only Keyword Arguments?

You can create a dictionary with initial key: value mappings by using a list of comma-separated arguments such as in dict(name = 'Alice', age = 22) to create the dictionary {'name': 'Alice', 'age': 22}. These are called keyword arguments because each argument value has its associated keyword.

>>> dict(name = 'Alice', age = 22)

{'name': 'Alice', 'age': 22}

How to Create a Dictionary Using an Iterable?

You can initialize your new dictionary by using an iterable as an input for the dict(iterable) function. Python expects that the iterable contains (key, value) pairs. An example iterable is a list of tuples or a list of lists. The first values of the inner collection types are the keys and the second values of the inner collection types are the values of the new dictionary.

>>> dict([(1, 'one'), (2, 'two')])

{1: 'one', 2: 'two'}

>>> dict([[1, 'one'], [2, 'two']])

{1: 'one', 2: 'two'}

>>> dict(((1, 'one'), (2, 'two')))

{1: 'one', 2: 'two'}

Note that you can use inner tuples, inner lists, outer tuples or outer lists—as long as each inner collection contains exactly two values. If it contains more, Python raises an ValueError: dictionary update sequence element.

>>> dict([(1, 'one', 1.0), (2, 'two', 2.0)])

Traceback (most recent call last): File "<pyshell#22>", line 1, in <module> dict([(1, 'one', 1.0), (2, 'two', 2.0)])

ValueError: dictionary update sequence element #0 has length 3; 2 is required

You can fix this ValueError by passing only two values in the inner collections. For example use a list of tuples with only two but not three tuple elements.

How to Create a Dictionary Using an Existing Mapping Object?

If you already have a mapping object such as a dictionary mapping keys to values, you can pass this object as an argument into the dict() function. Python will then create a new dictionary based on the existing key: value mappings in the argument. The resulting dictionary will be a new object so if you change it, the changes are not reflected in the original mapping object.

>>> d = {'Alice': 22, 'Bob': 23, 'Carl': 55}

>>> d2 = dict(d)

>>> d

{'Alice': 22, 'Bob': 23, 'Carl': 55}

If you now change the original dictionary, the change is not reflected in the new dictionary d2.

>>> d['David'] = 66

>>> d

{'Alice': 22, 'Bob': 23, 'Carl': 55, 'David': 66}

>>> d2

{'Alice': 22, 'Bob': 23, 'Carl': 55}

How to Create a Dictionary Using a Mapping Object and Keyword Arguments?

Interestingly, you can also pass a mapping object into the dict() function and add some more key: value mappings using keyword arguments after the first mapping argument. For example, dict({'Alice': 22}, Bob = 23) creates a new dictionary with both key:value mappings {'Alice': 22, 'Bob': 23}.

>>> dict({'Alice': 22}, Bob = 23)

{'Alice': 22, 'Bob': 23}

>>> dict({'Alice': 22}, Bob = 23, Carl = 55)

{'Alice': 22, 'Bob': 23, 'Carl': 55}

How to Create a Dictionary Using an Iterable and Keyword Arguments?

Similarly, you can also pass an iterable of (key, value) tuples into the dict() function and add some more key: value mappings using keyword arguments after the first mapping argument. For example, dict([('Alice', 22)], Bob = 23) creates a new dictionary with both key:value mappings {'Alice': 22, 'Bob': 23}.

>>> dict([('Alice', 22)], Bob = 23)

{'Alice': 22, 'Bob': 23}

>>> dict([('Alice', 22), ('Carl', 55)], Bob = 23)

{'Alice': 22, 'Carl': 55, 'Bob': 23}

Summary

Python’s built-in dict() function creates and returns a new dictionary object from the comma-separated argument list of key = value mappings.

For example, dict(name = 'Alice', age = 22, profession = 'programmer') creates a dictionary with three mappings: {'name': 'Alice', 'age': 22, 'profession': 'programmer'}.

>>> dict(name = 'Alice', age = 22, profession = 'programmer')

{'name': 'Alice', 'age': 22, 'profession': 'programmer'}

A dictionary is an unordered and mutable data structure, so it can be changed after creation.

I hope you enjoyed the article! To improve your Python education, you may want to join the popular free Finxter Email Academy:

---

Do you want to boost your Python skills in a fun and easy-to-consume way? Consider the following resources and become a master coder!

Where to Go From Here?

Enough theory, let’s get some practice!

To become successful in coding, you need to get out there and solve real problems for real people. That’s how you can become a six-figure earner easily. And that’s how you polish the skills you really need in practice. After all, what’s the use of learning theory that nobody ever needs?

Practice projects is how you sharpen your saw in coding!

Do you want to become a code master by focusing on practical code projects that actually earn you money and solve problems for people?

Then become a Python freelance developer! It’s the best way of approaching the task of improving your Python skills—even if you are a complete beginner.

Join my free webinar “How to Build Your High-Income Skill Python” and watch how I grew my coding business online and how you can, too—from the comfort of your own home.

Join the free webinar now!

The post Python dict() — A Simple Guide with Video first appeared on Finxter.

Last modified on August 23rd, 2020.

Photo editing effects will turn graphical elements to be expressive. With suitable effects, you can use a simple image and convey an idea. For example, you can bring logo to the foreground by blurring the background image.

The effects like image blur, transparency, shadowing creates attractive visual effects. There are many different image effects available. In fact, hundreds of them are available.

Online photo editing tools use a variety of methods to apply the effects on a target image. For example, either a CSS filter property or a SVG filter primitive can create an image blur effect.

Most of the visual effects are achievable with HTML5 and CSS3 filter properties. We will see how to make photo editing effects to blur, apply sepia, and vintage effect on a target image.

I created a simple image editing tool to apply blur, sepia, and vintage effect on a target image. Following is a live preview of the tool.

I have added a jQuery slider to allow you fiddle with the image editing effects between a min-max range.

What is inside?

1. Popular photo editing effects
2. Uses of image editing effects
3. About this example
4. File structure
5. Online photo editing UI to apply blur sepia effects
6. Managing image editing effects with jQuery slider
7. Blur image using CSS and SVG filter
8. How to apply sepia effect on an image
9. Applying various tones with vintage effects
10. Editing tool output with image Blur Sepia and Vintage effects

Popular photo editing effects

You can use photo editing effects and manipulate images in an innovative way. They cause visual conversion on the UI graphics. You can add tones, brightness, shadow, themes, and lot more effects on a photo.

There is almost no limit to add effects on a photo. In a previous article, I gave an image-editing example with image transition effects.

Below is a sample list of visual effects achievable with simple CSS.

• Grayscale
• Blur
• Brightness
• Contrast
• Opacity
• Saturate
• Sepia
• Invert

Uses of image editing effects

The photo editing may seem like a fun and easy job. But, it’s not true. Rather, it’s a real challenge to show your potential to give the best results.

I used some of the effects on the output of the image editing example scripts like fade-in-out image background.

Many of the image editing effects are most frequently required by the user. They are,

• Blur image – to highlight something important in the foreground.
• opacity – to add transparency for the product labels displayed on the shop gallery images.
• grayscale – to remove the color of an image.

With CSS filter property, these effects can give a combined result on a target UI element.

About this example

This example handles blur, sepia and vintage effect on an image element.

For applying the blur and sepia effects, there is a jQuery slider handle above the image target. It will allow you to change the intensity.

This code will preview four vintage tones in a row. On clicking the preview, the editor panel will apply the appropriate vintage effect.

There is an option to reset the applied image editing effects. Blur is the default effect the slider handler events apply.

File Structure

This screenshot shows the file structure of the image editing example code. It’s a pure CSS jQuery example that provides image editing features.

There are no third-party plugins used to achieve the editing effects on this example.

I have rendered a static image as a target for applying the blur and more effects. You may include an image upload option to render dynamic images.

Online photo editing UI to apply blur sepia vintage effects

This section shows the HTML of the online photo editing interface to allow image blur like effects.

The landing page has the complete HTML code for the image editing UI.

It shows the action buttons to choose the editing effects among blur, sepia and vintage.

index.php

<html>

<head>

<meta name="viewport" content="width=device-width, initial-scale=1">

<title>Image Effects Blur Sepia Vintage</title>

<link href="./assets/css/phppot-style.css" type="text/css" rel="stylesheet" />

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

<link href="./vendor/jquery/ui/jquery-ui.min.css" type="text/css" rel="stylesheet" />

</head>

<body> <div class="phppot-container"> <div class="container"> <input type='button' value='Blur' class="btn action selected" /> <input type='button' id='btnSpin' value='Sepia' class="btn action" /> <input type='button' value='Vintage' class="btn" id="vintage" /><input type='button' value='Reset' class="btn" id="reset" /> <div id="vintage-slide"> <?php for ($i = 1; $i <= 4; $i ++) { ?> <img src="./image/slide/vintage-slide<?php echo $i; ?>.png" class="vintage-effect" id="vintage-effect<?php echo $i; ?>" data-slide="<?php echo $i; ?>" /> <?php } ?> </div> <div class="image-demo-box"> <div id="slider"> <div id="slider-handle" class="ui-slider-handle"></div> </div> <img src='./image/cherry-bloosm.jpg' id='image' /> <div class="overlay"></div> </div> </div> </div> <script src='./vendor/jquery/jquery-3.3.1.js' type='text/javascript'></script> <script src='./vendor/jquery/ui/jquery-ui.min.js' type='text/javascript'></script> <script src='./assets/js/image-edit.js'></script>

</body>

</html>

After selecting the action buttons, the slider control will supply the value of the selected editing effect.

The reset button helps revert back to the original state of the rendered image element.

Managing image editing effects with jQuery slider

This jQuery script initializes UI slider on document ready. It applies the selected effects on an image by clicking the blur, sepia, vintage buttons. On dragging the slider handle the value from the ui.value has the effect’s intensity.

On selecting each effect, the slider reset will happen to bring the handle to the min position.

The reset button will clear the applied photo effects on the image. It reverts the target image back to its original.

assets/js/image-edit.js

$(document).ready(function() { $("#slider").slider({ range : "min", min : 0, max : 100, slide : function(event, ui) { var val = ui.value; var action = $('.action.selected').val(); applyEffect(action, val); } }); $('.action').on('click', function() { resetSlider(); $('.btn').removeClass("selected"); $(this).addClass("selected"); }); $('#vintage').on('click', function() { $('.btn').removeClass("selected"); $(this).addClass("selected"); $("#slider").hide(); $("#vintage-slide").show(); vintage(1); }); $('.vintage-effect').on('click', function() { var val = $(this).data("slide") vintage(val); }); $('#reset').on('click', function() { resetSlider(); $('.btn').removeClass("selected"); $('.btn').first().addClass("selected"); }); });

function applyEffect(action, val) { if (action == 'Blur') { blur(val); } else if (action == 'Sepia') { sepia(val); }

}

function blur(val) { $("#image").css("filter", "blur(" + val + "px)");

}

function sepia(val) { $("#image").css("filter", "sepia(" + val + "%)");

}

function vintage(val) { $('.vintage-effect').removeClass("selected") $("#vintage-effect"+val).addClass("selected"); $(".overlay").show(); $(".overlay").css("background", "url('./image/vintage-bg"+val+".jpg')")

}

function resetSlider() { $("#slider").show(); $("#vintage-slide").hide(); $(".overlay").hide(); var options = $("#slider").slider('option'); $("#slider").slider("value", options.min); var action = $('.action.selected').val(); applyEffect(action, options.min);

}

Blur image using CSS and SVG filter

As shown in the above example, blur image action is possible with CSS filter function blur(). It accepts a value as its parameter to apply the blur filter on the target element.

The CSS in the below code will apply the blur effect on the image element of the HTML.

<style>

#image { margin: 50px auto; border: #f6f5f6 10px solid; width: 500px; filter: blur(10px);

}

</style>

<img src='./image/cherry-bloosm.jpg' id='image' />

This example has a slider’s drag event-based photo editing effects. So, the jQuery script manages the CSS filter property on dragging the slider handle.

Blur image with SVG filter and CSS url() function

In the below code, it shows yet another way to blur images HTML element. It uses CSS url() function to apply the blur effect.

The url() function accepts a path or a selector string to apply the filter via CSS.

This code has the svg with <fegaussianblur> filter primitive. The blur intensity will vary based on the stdDeviation attribute’s value.

<style>

#image{ filter:url('#blur');

}

</style>

<img src='./image/cherry-bloosm.jpg' id='image' />

<svg> <defs> <filter id="blur"> <feGaussianBlur in="SourceGraphic" stdDeviation="1,4" /> </filter> </defs>

</svg>

How to apply sepia effect on an image

Sepia is one of the photo editing effects used in this example to apply on a HTML image. It gives light reddish or brownish tones to monochromatic photos.

There is yet another CSS filter function sepia() to apply this effect on an image.

The CSS sepia() function may have a number or percentage as a parameter. All the below CSS styles are valid to create the sepia() effect.

filter:sepia(0);

filter:sepia(25%);

filter:sepia(0.3);

filter:sepia(1);

Applying various tones with vintage effects

The vintage effect on a photograph gives an ancient tone to the photo. It’s an art to giving a flimsy tone to the modern photo output.

In this example, I have used template films to create a vintage effect on an image. It uses four types of films as a background to add different tones to the image element.

There are plugins to convert photos with vintage effects. For getting a basic result, the combination of the basic photo editing effects may help.

Editing tool output with image Blur Sepia and Vintage effects

In the below screenshot, I have shown all the three photo effects in a single output window.

Conclusion

We have seen how to apply three of the popular photo effects blur, sepia and vintage on an image. Though there are more possible effects, this example code is a very good beginning to achieve all.

I hope, applying effects with jQuery slider is more comfortable than any other type of input. I prefer slider whenever required to collect input between ranges.

Applying a creative combinational photo editing effects will give impressive results. Not only beautification but also helps to convey your thoughts via graphical representation. Rock on!

Download

↑ Back to Top