Example 1: python dictionary
#Creating dictionaries
dict1 = {'color': 'blue', 'shape': 'square', 'volume':40}
dict2 = {'color': 'red', 'edges': 4, 'perimeter':15}
#Creating new pairs and updating old ones
dict1['area'] = 25 #{'color': 'blue', 'shape': 'square', 'volume': 40, 'area': 25}
dict2['perimeter'] = 20 #{'color': 'red', 'edges': 4, 'perimeter': 20}
#Accessing values through keys
print(dict1['shape'])
#You can also use get, which doesn't cause an exception when the key is not found
dict1.get('false_key') #returns None
dict1.get('false_key', "key not found") #returns the custom message that you wrote
#Deleting pairs
dict1.pop('volume')
#Merging two dictionaries
dict1.update(dict2) #if a key exists in both, it takes the value of the second dict
dict1 #{'color': 'red', 'shape': 'square', 'area': 25, 'edges': 4, 'perimeter': 20}
#Getting only the values, keys or both (can be used in loops)
dict1.values() #dict_values(['red', 'square', 25, 4, 20])
dict1.keys() #dict_keys(['color', 'shape', 'area', 'edges', 'perimeter'])
dict1.items()
#dict_items([('color', 'red'), ('shape', 'square'), ('area', 25), ('edges', 4), ('perimeter', 20)])
Example 2: dictionary in python
# Dictionaries in Python are used to store set of data like Key: Value pair
# the syntax of a dictionary in Python is very simple we use {} inside that
# we define {Key: Value}, to separate multiple values we use','
programming_dictionary = {
"Bug": "An error in a program that prevents the program from running as expected.",
"Function": "A piece of code that you can easily call over and over again.",
"Loop": "The action of doing sommething again and again",
}
# to retrieve the values from a dictionary we use the Key name as an Index
# retrieving the Function's definition
print(programming_dictionary["Function"]) # this will print the definition of Function
# if you wanna print all the entries in the dictionary you can do that by for loop
for key in programming_dictionary:
print(programming_dictionary[key]) # prints all entries
# adding items to a dictionary
# the following code will add another entry to the dictionary called Variable
programming_dictionary["Variable"] = "The label to store some sort of data"
print(programming_dictionary["Variable"])
# editing the values of a key
# editing the value of variable
programming_dictionary["Variable"] = "Variables are nothing but reserved memory locations to store values. This means that when you create a variableyou reserve some space in memory"
# if you learnt something from this please upvote it
Example 3: how to use dictionaries in python
student_data = {
"name":"inderpaal",
"age":21,
"course":['Bsc', 'Computer Science']
}
#the keys are the left hand side and the values are the right hand side
#to print data you do print(name_of_dictionary['key_name'])
print(student_data['name']) # will print 'inderpaal'
print(student_data['age']) # will print 21
print(student_data['course'])[0]
#this will print 'Bsc' since that field is an array and array[0] is 'Bsc'
Example 4: dictionary in python
tel = {'jack': 4098, 'sape': 4139}
tel['guido'] = 4127
print(tel)
# OUTPUT {'jack': 4098, 'sape': 4139, 'guido': 4127}
print(tel['jack'])
# OUTPUT 4098
del tel['sape']
tel['irv'] = 4127
print(tel)
# OUTPUT {'jack': 4098, 'guido': 4127, 'irv': 4127}
print(list(tel))
# OUTPUT ['jack', 'guido', 'irv']
print(sorted(tel))
# OUTPUT ['guido', 'irv', 'jack']
print('guido' in tel)
# OUTPUT True
print('jack' not in tel)
# OUTPUT False
Example 5: python dictionary
#title :Dictionary Example
#author :Josh Cogburn
#date :20191127
#github :https://github.com/josh-cogburn
#====================================================
thisdict = {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
#Assigning a value
thisdict["year"] = 2018
Example 6: dictionary in python
d = {'key1':'value1','key2':'value2'}
print(d) # to print full dictionary
l=d.keys
print(l) # to print keys
b=d.values
print(b)#to print values in dictionary