Example 1: 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 2: 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 3: python make a dictionary
#title : Dictionary Example
#author : Joyiscold
#date : 2020-02-01
#====================================================
thisdict = {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
#Assigning a value
thisdict["year"] = 2018
Example 4: all dictionary functions in python
clear() - Removes all the elements from the dictionary
copy() - Returns a copy of the dictionary
fromkeys() - Returns a dictionary with the specified keys and value
get() - Returns the value of the specified key
items() - Returns a list containing a tuple for each key value pair
keys() - Returns a list containing the dictionary's keys
pop() - Removes the element with the specified key
popitem() - Removes the last inserted key-value pair
setdefault() - Returns the value of the specified key. If the key does not exist: insert the key, with the specified value
update() - Updates the dictionary with the specified key-value pairs
values() - Returns a list of all the values in the dictionary
Example 5: 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 6: python dict
# decleration
my_dict = {
'spam': 'eggs',
'foo': 4,
100: 'bar',
2: 0.5
}
# access single values from the dictionary
print(my_dict['spam']) # eggs
print(my_dict['foo']) # 4
print(my_dict[100]) # bar
print(my_dict[2]) # 0.5
# iterate over the dictionary
for key, value in my_dict.items():
print(key, value)
# get length of the dictionary
print(len(my_dict)) # 4
# modify the dictionary
my_dict['baz'] = 'qux' # adds a pair
my_dict['baz'] = 'quxx' # also updates it
del my_dict['spam'] # removes a pair
# other methods
print(my_dict.copy()) # Returns a copy of the dictionary
print(my_dict.fromkeys('added', 100)) # Returns a dictionary with the specified keys and their values
print(my_dict.get('foo')) # Returns the value of the specified key
print(my_dict.items()) # Returns a list containing a tuple for each key value pair
print(my_dict.keys()) # Returns a list containing the dictionaries keys
print(my_dict.values()) # Returns a list of all the values in the dictionary
my_dict.setdefault('a', 'b') # Returns the value of the specified key. If the key does not exist: insert the key, with the specified value
my_dict.pop('foo') # Removes the element with the specified key
my_dict.popitem() # Removes the last inserted key-value pair
my_dict.update({'baz': 'val'}) # Updates the dictionary with the specified key-value pairs
my_dict.clear() # Removes all the elements from the dictionary