Python Dictionaries — Update data, loop through 🐍

2 min readJan 4, 2023

Dictionaries are an interesting data structure in Python. In other programming languages like JavaScript, you can call it an object.

Getting back to our example, we can change the value of a dictionary key as shown below:

dict = {"name": "Nitin", "age": 34, "gender": "male"}
dict["name"] = "ABC"
dict["name"]

Result -> ABC

Pretty easy isn’t it?

Add a new key-value pair

Now let’s look at how we can add a new key-value pair to a dictionary. Python dictionary has an update method that gives you the freedom to add or update a new key-value pair.

dict = {"name": "Nitin", "age": 34, "gender": "male"}
dict.update({"city": "Pune"})
dict

Result -> {"name": "Nitin", "age": 34, "gender": "male", "city": "Pune"}

Update a key-value pair

Updating a key-value pair is pretty simple.

dict = {"name": "Nitin", "age": 34, "gender": "male"}
dict.update({"city": "Delhi"})
dict
Result -> {"name": "Nitin", "age": 34, "gender": "male", "city": "Delhi"}

If you observe in the above example, the new key-value pair is added with the curly braces as an argument to the update method.

If the key-value pair already exists in the dictionary then the value will be replaced and if the key-value pair does not exist then this method will create a new key-value pair.

Loop over the dictionary

We can also loop over the dictionary data using the for iterator and it's quite easy.

dict = {"name": "Nitin", "age": 34, "gender": "male"}
for data in dict.keys():
    print(data)

Result ->
name
age
gender

Here we loop over the dictionary keys and as a result, the keys are getting printed.

We can also loop over the dictionary keys’ values using the for iterator

dict = {"name": "Nitin", "age": 34, "gender": "male"}

for data in dict.values():
    print(data)

Result ->
Nitin
34
male

Easy to understand? 💡

A dictionary contains

Loop over the dictionary
Add or update the dictionary data

This would look similar to an object in JavaScript

Conclusion 📗

There are more posts on the way related to the dictionaries…So keep reading.

Thanks in advance for reading this article…🚀

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