Iterate through list of dictionaries in Python
In this article, we will learn how to iterate through a list of dictionaries.
List of dictionaries in use:
[{‘Python’: ‘Machine Learning’, ‘R’: ‘Machine learning’},
{‘Python’: ‘Web development’, ‘Java Script’: ‘Web Development’, ‘HTML’: ‘Web Development’},
{‘C++’: ‘Game Development’, ‘Python’: ‘Game Development’}, {‘Java’: ‘App Development’, ‘Kotlin’: ‘App Development’}]
Method 1: Using indexing
This is a direct method, where list elements are extracted using just the index.
Syntax:
list[index]
Example:
Python3
languages = [
{
"Python" : "Machine Learning" ,
"R" : "Machine learning" ,
},
{
"Python" : "Web development" ,
"Java Script" : "Web Development" ,
"HTML" : "Web Development"
},
{
"C++" : "Game Development" ,
"Python" : "Game Development"
},
{
"Java" : "App Development" ,
"Kotlin" : "App Development"
}
]
print (languages[ 0 ])
print (languages[ 1 ])
print (languages[ 2 ])
print (languages[ 3 ])
|
Output:
{‘Python’: ‘Machine Learning’, ‘R’: ‘Machine learning’}
{‘Python’: ‘Web development’, ‘Java Script’: ‘Web Development’, ‘HTML’: ‘Web Development’}
{‘C++’: ‘Game Development’, ‘Python’: ‘Game Development’}
{‘Java’: ‘App Development’, ‘Kotlin’: ‘App Development’}
After using indexing to particular dictionaries, now we can treat each item of the list as a dictionary,
Example: Extracting values from a particular dictionary
Python3
languages = [
{
"Python" : "Machine Learning" ,
"R" : "Machine learning" ,
},
{
"Python" : "Web development" ,
"Java Script" : "Web Development" ,
"HTML" : "Web Development"
},
{
"C++" : "Game Development" ,
"Python" : "Game Development"
},
{
"Java" : "App Development" ,
"Kotlin" : "App Development"
}
]
for key, val in languages[ 0 ].items():
print ( "{} : {}" . format (key, val))
|
Output:
Python : Machine Learning
R : Machine learning
Method 2: Using keys()
After iterating to a list the keys from the dictionary can further be extracted using the keys() function.
Example: Extracting key values
Python3
languages = [
{
"Python" : "Machine Learning" ,
"R" : "Machine learning" ,
},
{
"Python" : "Web development" ,
"Java Script" : "Web Development" ,
"HTML" : "Web Development"
},
{
"C++" : "Game Development" ,
"Python" : "Game Development"
},
{
"Java" : "App Development" ,
"Kotlin" : "App Development"
}
]
for i in languages:
for key in i.keys():
print (key)
print ( "-------------" )
|
Output:
Python
R
————-
Python
Java Script
HTML
————-
C++
Python
————-
Java
Kotlin
————-
The list is simply iterated using list comprehension and the dictionaries are printed.
Example: Extracting keys using list comprehension
Python3
languages = [
{
"Python" : "Machine Learning" ,
"R" : "Machine learning" ,
},
{
"Python" : "Web development" ,
"Java Script" : "Web Development" ,
"HTML" : "Web Development"
},
{
"C++" : "Game Development" ,
"Python" : "Game Development"
},
{
"Java" : "App Development" ,
"Kotlin" : "App Development"
}
]
print ( * [key for i in languages for key in i.keys()], sep = "\n" )
|
Output:
Python
R
Python
Java Script
HTML
C++
Python
Java
Kotlin
Last Updated :
22 Nov, 2021
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