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Python.Engineering Wiki Javascript Iterates Through The Object’S Key-Value Pairs

Javascript Iterates Through The Object’S Key-Value Pairs

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Michael Zippo Michael Zippo 04.11.2021

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The items () method, keys () method, and values ‚Äã‚Äã() method return values ‚Äã‚Äãthat you can use to iterate over a dictionary in Python. items () returns both keys and values ‚Äã‚Äãin a Python dictionary. keys () returns the keys in a dictionary. values ‚Äã‚Äã() returns values ‚Äã‚Äãin a dictionary. You can also use a for loop to iterate through a Python dictionary.

When working with d ictionaries, you may want to iterate over the values ‚Äã‚Äãyou have memorized.

For example, suppose you create a program for a librarian that displays the title, description, author, and other relevant information of a specific book. You want to scroll through the dictionary that stores this data so that you can show it to the user of your program.

There are several ways to scroll through a dictionary. This tutorial will explain how to iterate through a dictionary using a for, items () and keys () loop. We’ll also explore an example of each of these approaches used to browse a dictionary.

Dictionary Update

Python Dictionaries stores data in a key-value structure. This means that each value is assigned a key which can be used to refer to that particular value.

Here is an example dictionary in Python:

Our dictionary uses a colon (:), which separates our keys and our values ‚Äã‚Äã. The words to the left of the colon are the keys, which in this case are title, author, publication_date and in_stock . These keys are all formatted as strings.

Python Iterate through dictionary

You can iterate through a Python dictionary using the keys (), items (), and values ‚Äã‚Äã() methods. keys () returns an iterable list of dictionary keys. items () returns key-value pairs in a dictionary. values ‚Äã‚Äã() returns the values ‚Äã‚Äãof the dictionary. You can also use a for loop to iterate through a dictionary.

Say wanted to know how many books your library had in stock. You might want to go through all the dictionaries to calculate the total quantity for each book.

Iterate using for Loop

Dictionaries are iterable objects, which means you can cycle through them like any other object. Perhaps the easiest way to scroll through a dictionary is to use a Python loop for . This loop allows you to iterate through each value in the dictionary individually.

Suppose you are writing a program for a librarian. You want to print the keys and values ‚Äã‚Äãfor a specific book to the console. Each key-value pair should be printed to the console on a new line. You can do this using the following code:

Our code returns the following:

To start, we declare a Python variable called book which stores four keys and values. This variable stores a value in the data type of the dictionary.

Next, we declare an for loop that iterates over each value in our dictionary. The for loop prints both the key and the value associated with that key to the console.

Iterate using items ()

dictionary.items () converts each key-value pair in a dictionary into a tuple. Using a for loop and the items () method, you can iterate through all the keys and values ‚Äã‚Äãin a list.

Let’s say we still want to go through our dictionary of books. But we want our values ‚Äã‚Äãto appear as a list of tuples. We could do this using the following code:

Our code returns a list of tuples:

Let’s define a for loop that iterates through our book dictionary using items (). items () converts each key-value pair into a tuple, which we can then access in our for loop. As you can see, each key-value pair has been printed to the console as a tuple.

This approach can be useful if you want to convert every value in your dictionary to a tuple while you iterate.

Iterate using the () keys

Often you might just want to scroll through the keys of a dictionary.

The librarian we work with asked us to compile a list of the information the library has on each book. In our terms, that means the librarian wants a list of keys stored in our dictionary.

We could use the method keys from the Python dictionary () to get a list of keys and print them to the console. Here is the code we would use to do this:

Our code returns:

In our code, we define an for loop that uses keys () to find the keys in our dictionary. Then the loop goes through each of these keys and prints them to the console. As you can see, our code returned the names of our four keys.

Iterate using values ‚Äã‚Äã()

The Python Dictionary values () allows to iterate the values ‚Äã‚Äãof a dictionary in Python. This method works the same as keys (), but returns the values ‚Äã‚Äãto a dictionary.

Our librarian wants us to print the values ‚Äã‚Äãfor each item in the book dictionary entry for The Great Gatsby on the console. We could do this using the following code:

Our code returns:

See Repl.it of this tutorial: