# 2.8: Dictionary

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## Overview

Use KEY:VALUE Pair

• Use Curly Brackets
• Mutable
• Unordered
• use KEY:VALUE pair separated by commas
• Values can be
• lists
• other dictionaries
• strings, numbers
• Are an object class with methods

## Simple Dictionary

z_alkali_dict={"Lithium":3,"Sodium":11,"Potassium":19, "Rubidium":37, "Caesium":55,"Francium":87}
#call the dictionary
z_alkali_dict
Hello world!

## Dictionary of lists

First, create the lists.  Note, nothing happens as you have to print something, add  the following to the end of the script

print("list created")

name_halogen=['fluorine', 'chlorine', 'bromine', 'iodine', 'astatine','tennessine']
z_halogen=[9,17,35,53,85,117]
a_halogen=[18.99840316,35.45,79.90,126.9045,209.98715,294.211]
symbol_halogen=["F","Cl","Br","I","At","Ts"]
Hello world!

Make the dictionary and call it

hal_dict={'name':name_halogen,"atomic_number":z_halogen,"atomic_weight":a_halogen}
#call it
hal_dict
        hello world


### Use Key to Call Values

Here we can use a key to get its value

print("the names of the halogens are ", hal_dict['name'])
        hello world


After running the above code, modify it to get the atomic weights of the halogens

#### Use list index numbers

print("The heaviest halogen is ", hal_dict['name'][-1])
print("The heaviest halogen is", hal_dict['name'][-1],", it weighs", hal_dict['atomic_weight'][-1],"amu.")

Hello world!

## Methods

hal_dict['name'][2].upper()
        hello world


Print the keys

hal_dict.keys()
Hello world!

Print the values

hal_dict.values()
        hello world


Print the

print(hal_dict)
print("\n 5*' * '\n")
hal_dict.items()
Hello world!

## Methods

This page titled 2.8: Dictionary is shared under a not declared license and was authored, remixed, and/or curated by Robert Belford.