How we can create dictionaries by multiple ways in python ?
Dictionary in python is one of the important datatype which is used to store data values in key : value pair.
Syntax of dictionary :
dictionary_name = {key1: value1, key2: value2}where,
- key1, key2… represents keys in a dictionary. These keys can be of any data type like string, integer, tuple, etc. But keys needs to be unique.
- value1, value2… represents values in dictionary. These values can be numbers, strings, list or list within a list etc.
- key and value is separated by : symbol.
- key-value pair symbol is separated by , symbol.
Approach-1: Creating Empty Dictionary :
By 2 ways we can create empty dictionary.
Method-1 : By using { } empty brackets :
Let’s see the implementation of it with a program.
#Program :
# Empty dictionary created using empty brackets
covid_case_dict = {}
print(covid_case_dict)Output :
{ }Method-2: By using using dict() :
Let’s see the implementation of it with a program.
#Program : # Empty dictionary created using dict() covid_case_dict = dict() print(covid_case_dict)
Output :
{ }Approach-2: Creating Dictionaries with literals :
By passing key : value pairs literals we can create dictionary.
Let’s see the implementation of it with a program.
#Program :
# dictionary created using key-value literals
covid_case_dict = {"January":100000, "February":200000, "March":300000}
print(covid_case_dict)Output :
{"January":100000, "February":200000, "March":300000}Approach-3: Creating Dictionaries by passing parameters in dict constructor :
By creating dictionary constructor and passing  key-value pairs within it also we can create a dictionary.
Let’s see the implementation of it with a program.
#Program : #dictionary created using dictionary constructor covid_case_dict = dict(January=100000, February=200000, March=300000) print(covid_case_dict)
Output :
{"January":100000, "February":200000, "March":300000}Approach-4: Creating Dictionaries by a list of tuples :
We can create a dictionary by passing list of tuple within dict constructor.
Let’s see the implementation of it with a program.
#Program :
# list of tuples
list_of_Tuples = [("January",100000), ("February",200000), ("March",300000)]
#dictionary created by passing tuple in dict constructor
covid_case_dict = dict(list_of_Tuples)
print(covid_case_dict)Output :
{"January":100000, "February":200000, "March":300000}Approach-5: Creating a Dictionary by a list of keys and initializing all with the same value :
We can create a dictionaries by assigning same vales to all the keys.
Suppose we a dictionary of keys. Let’s see how we can initialize all keys with same value.
#Program : # list of keys covid_case_list = ["Januray", "February", "March"] # create and Initialize a dictionary #use list elements as keys and with same value 100000 covid_case_dict = dict.fromkeys(covid_case_list,100000 ) print(covid_case_dict)
Output :
{"January":100000, "February":100000, "March":100000}Approach-6: Creating a Dictionary by two lists :
If we have two lists, then also we can create a dictionary. For that we can use the elements of the first list as keys and we can use the elements of the second list as values.
In python there is a zip( ) function which we will be used and it will iterate over two lists parallelly.
Let’s see the implementation of it with a program.
#Program : # First list, its elements will be used as keys covid_case_list1 = ["Januray", "February", "March"] # Second list, its elements will be used as values covid_case_list2 = [100000, 200000, 300000] #two lists are merged using zip() to create dictionary covid_case_dict = dict( zip(covid_case_list1,covid_case_list2)) print(covid_case_dict)
Output :
{"January":100000, "February":100000, "March":100000}