Dictionary homework help
Dictionaries, which we are accustomed to are the ones that contain words and their meanings. Dictionaries have a different definition when it comes to python programming. Although the idea is the same in the two cases, some words resemble the keys and the key value that can be interpreted as the meaning of the words in the dictionary. There are a lot of things that you probably do not know about the python dictionaries. This article will serve as an introduction to python dictionaries. In case there is anything that you do not understand about dictionaries, you can contact our online dictionary experts
Here’s what this article will focus on. What are dictionaries, the basic characteristics of Python dictionaries, similarities and differences between a dictionary and a list, and finally dictionary data manipulation such as accessing the elements of the dictionary?
And when you are done, we expect you will be introduced to what dictionaries are and how to manipulate them.
What is a dictionary?
They are defined as an unordered collection of items. Normally they are enclosed in curly brackets. Dictionaries in python have a key and a key-value separated by a colon. The use of a comma further separates the pairs. Dictionaries belong to a family of the iterable in python. Here we imply those data types that can be iterated, i.e., ‘for loops’ can be used on the data.
How to create a dictionary
The simplest way you can create a dictionary is by using creating a dictionary command. You have to use curly braces and place the items inside them. The items should have a key and a value. They are well expressed if written in the form of key: value
The values can hold any data type, but the keys are restricted to holding only strings, numbers, or tuples. However, one key requirement is that the keys must be unique. You can repeat the values but not the keys.
Another method to construct a dictionary is by using the dict () method. The requirement for building a dictionary is still the same.
Similarities and differences between a list and a dictionary
Lists and dictionaries can all be iterated by using ‘for loops’ or any other means. Despite these common similarities, there are other similarities that they share which include:-
• They are mutable. Mutability implies that the individual items in a list or a dictionary can be changed after their initial writing
• They are dynamic as their sizes can be increased or decreased
• They can be nested. This idea can be derived in a ‘for loop’ statement, which can contain a ‘for loop’ inside a ‘for loop.’ In the same manner, a list can contain a list inside a list; likewise, a dictionary can contain a dictionary inside it. Nestedness in python does not restrict the data type. A list could contain a dictionary or a tuple.
The major differences between a dictionary and a list
Those list elements can only be accessed by their position in the list, whereas their keys can only access the dictionary elements.
Accessing the elements of a dictionary
A dictionary, as we have explained in the above section, uses keys to access its elements. The elements can be accessed by using the keys inside a square bracket or the get () function. Make sure that the key that you are using is in the dictionary. If it’s not there, while using the square brackets, then KeyError will be raised. The get () function will return none if it is not found.
Changing or adding the elements in a dictionary
One of the key characteristics of dictionaries is that they are mutable. It’s possible to add or change its items. In python, this is accomplished by using the homework operator.
Be cautious with this method, as it can change or add a new item depending on whether the key is available or not.
Deleting elements from a dictionary
As much as we can add a new item, we can also delete the item. The method that can be used to remove an item is the pop () method, which is still applicable to lists. The pop () method deletes an item of a dictionary using the key.
Additionally, we can remove all the items at once using the clear () method. All the items can be removed at once, using the clear () method.
A substitute for the pop () method can be del keyword, which literary works in the same manner.
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