Convert list to dictionary python 3

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A close runner-up to using the dict constructor is to use the native syntax of a dict comprehension not a list comprehension, as others have mistakenly put it :. In Python 2, zip returns a list, to avoid creating an unnecessary list, use izip instead aliased to zip can reduce code changes when you move to Python 3.

convert list to dictionary python 3

If we look at the help on dict we see that it takes a variety of forms of arguments:. The optimal approach is to use an iterable while avoiding creating unnecessary data structures. In Python 2, zip creates an unnecessary list:. Since we want to avoid creating unnecessary data structures, we usually want to avoid Python 2's zip since it creates an unnecessary list.

In the first two cases, an extra layer of non-operative thus unnecessary computation is placed over the zip iterable, and in the case of the list comprehension, an extra list is unnecessarily created. I would expect all of them to be less performant, and certainly not more-so. We use min because these algorithms are deterministic. We want to know the performance of the algorithms under the best conditions possible. If the operating system hangs for any reason, it has nothing to do with what we're trying to compare, so we need to exclude those kinds of results from our analysis.

If we used meanthose kinds of events would skew our results greatly, and if we used max we will only get the most extreme result - the one most likely affected by such an event.

In python 3. I presume we mean dict zip That does sound like a fairly unusual use case. It does makes sense that the most direct calls would dominate in large datasets, and I wouldn't be surprised if OS hangs are dominating given how long it would take to run that test, further skewing your numbers. And if you use mean or max I would consider your results meaningless.

And we see here that dict zip If you need to transform keys or values before creating a dictionary then a generator expression could be used. More on dict comprehensions herean example is there:.

But make sure that length of the lists will be same. I had this doubt while I was trying to solve a graph-related problem. The issue I had was I needed to define an empty adjacency list and wanted to initialize all the nodes with an empty list, that's when I thought how about I check if it is fast enough, I mean if it will be worth doing a zip operation rather than simple assignment key-value pair.

After all most of the times, the time factor is an important ice breaker.In this article we will discuss different ways to convert a single or multiple lists to dictionary in Python. Now we want to create a dictionary with all elements in this list as keys.

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For each key value will be same i. It returns a dictionary with items in list as keys. All dictionary items will have same value, that was passed in fromkeys. If no default value was passed in fromKeys then default value for keys in dictionary will be None. Zip accepts a number of iterable objects and returns a list of tuples. Each entry in tuple contains an element from each iterable object.

We have passed two lists objects in zipso it will return a list of tuples, where each tuple contains an entry from both the lists. Then we created a dictionary object from this list of tuples. Entries in first column will become the key and entries in second column will the values in the new dictionary. Contents of dictionary will be. Top 5 online Python courses for beginners in Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed. Python : How to convert a list to dictionary? Varun June 30, Python : How to convert a list to dictionary?

Following conversions from list to dictionary will be covered here, Convert a List to Dictionary with same values Convert List items as keys in dictionary with enumerated value Convert two lists to dictionary Convert a list of tuples to dictionary Convert a List to Dictionary with same values Suppose we have a list of strings i.

List of strings. Converting a list to dictionary with list elements as keys in dictionary. All keys will have same value. Converting a list to dictionary with list elements as values in dictionary. List of ints. Create a zip object from two lists. Create a dictionary from zip object. Dictionary from two Lists hello :: 56 here :: 43 this :: 97 test :: 43 at :: 23 now :: If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide. Given a dictionary, write a Python program to convert the given dictionary into list of tuples.

Python code to convert dictionary into list of tuples. Converting into list of tuple. Output: [ 'Geek', 31'for', 12'Geeks', 10 ].

Python | Convert string dictionary to dictionary

Output: [ 'for', 12'Geeks', 10'Geek', 31 ]. Converting from zip object to list object. Output: [ 'Geek', 31'Geeks', 10'for', 12 ]. Output: [ 'Geeks', 10'for', 12'Geek', 31 ]. Recommended Posts: Python Convert a list of Tuples into Dictionary Python Convert list of tuples to dictionary value lists Python Convert Tuples to Dictionary Python Convert string tuples to list tuples Python List of tuples to dictionary conversion Python Convert list of tuples to list of strings Python Convert list of strings to list of tuples Python Convert list elements to bi-tuples Python Convert list of tuples into digits Python Convert String to list of tuples Python Convert list of tuples into list Python Convert list of tuples to list of list Python Convert List of Dictionary to Tuple list Python Convert a list to dictionary Python Convert list of tuple into dictionary.

Check out this Author's contributed articles. Load Comments.The function dict creates a new dictionary with no items. Accessing elements of a dictionary. Let us see how to do that in Python…. Sounds crazy!!! Finally: We print all the Key and Value properties with the Console.

If you just type the name of the variable myDict, all the key value pairs in the dictionary will be printed. Separate the key and value with colons : and with commasbetween each pair. If the items hae different values, Python figures out the comparison between them. This you can do with the zip function. Dictionary elements have no intrinsic order. The key, value pairs are separated with commas. Python first compares the sorted key-value pairs.

convert list to dictionary python 3

However, while iterating over each element, we will get the key and not the value of the element, therefore, to access the value of the element, we have to use the key just like index, For example: myDictionary[key].

The indent arguments come in handy to prettify the output if you have deeply nested data structures.

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Print all key-value pairs using a loop : This is the simplest way to print all key-value pairs of a dictionary. The value can be almost any Python object. In other words, what is the key with the maximum value in the dictionary?

The keys in a dictionary must be immutable objects like strings or numbers. In the following example we will delete the key ali and its related value by using del function.

The main operations on a dictionary are storing a value with some key and extracting the value given the key. Python String to Dictionary. 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.

A dictionary is an associative array also known as hashes. What is Python dictionary? Remove Key Value From Dictionary. Python dictionaries are called associative arrays or hash tables in other languages.

These methods are useful in loops that need to step through dictionary entries one by one. Simplest way to add item to dictionary Converting list of lists into a dictionary of dictionaries in Python ; How to sum elements in list of dictionaries if two key values are the same ; Create dict from list of list ; Expand a dict containing list items into a list of dict pairs Dictionaries are collections that are indexed by keys, which can be any immutable type.

You have to use the new key and assign the new value to it. Certainly, it would be a handful to know a bit about Dictionary in Python.

And this is all that is required to iterate through all key-value pairs items of a dictionary in Python. We are creating the dictionary from the list, so Python Dict fromKeys can get the key values from the Python List and then convert it to the dictionary keys. I used this dictionary format internally within the another piece of code I am writing and had no problems.

It is mutable and can contain mixed types. This is not really a robust solution, but you get the idea.Converting a list of lists to a dictionary can be useful in certain situations.

We can think of a Python list of lists as a database table where the outer list represent the table and the inner lists represent the rows. A database table has a primary key and the rest of the fields hold the data. We can use that key as a dictionary key and the rest of data as the value. Let us see how to do that in Python…. Dictionary comprehensions in Python is a cool technique to produce dictionary data structures in a neat way. Assume we have a list of cars in a list of lists format.

We need to convert that into a dictionary format. For each list we extract the first item as the key and the rest of the items as the value list. Extracting the key is as simple as indexing an array. Extracting the rest of items can be achieved using slicing. Take a look…. Again almost the same format but using a generator expression to construct a dictionary object.

For more information about iterators and generators you may check the following article.

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Here is an example…. The same logic but using a regular loop is demonstrated below.

Converting a List into a Dictionary in Python

Nothing drastically different except the coding style. Save my name, email, and website in this browser for the next time I comment. Skip to content.

Home Code Snippets how to convert list of lists to dictionary in python. List of lists.

convert list to dictionary python 3

Convert to dictionary. Print output. Output dictionary. Print to see output. Add a Comment Cancel reply Your email address will not be published.Interconversions of data types have been discussed many times and have been quite a popular problem to solve. This article discusses yet another problem of interconversion of dictionary, in string format to a dictionary.

This task can easily be performed using the inbuilt function of loads of json library of python which converts the string of valid dictionary into json form, dictionary in Python.

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The above method can also be used to perform a similar conversion. Function safer than the eval function and can be used for interconversion of all data types other than dictionary as well. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment?

Please use ide. Method 1 : Using json. Python3 code to demonstrate. Check out this Author's contributed articles. Load Comments. Python3 code to demonstrate convert dictionary string to dictionary using json.

Python How to Convert List of Tuples to Dictionary

Python3 code to demonstrate convert dictionary string to dictionary using ast.Sometimes you might need to convert a tuple to dict object to make it more readable. In this article, we will try to learn how to convert a list of tuples into a dictionary.

Here we will find two methods of doing this. Method 1 : Use of setdefault. Here we have used the dictionary method setdefault to convert the first parameter to key and the second to the value of the dictionary. Using the append function we just added the values to the dictionary. This is a simple method of conversion from a list or tuple to a dictionary. Here we pass a tuple into the dict method which converts the tuple into the corresponding dictionary. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide. Python code to convert into dictionary. Driver Code. Recommended Posts: Python Convert dictionary to list of tuples Python Convert list of tuples to dictionary value lists Python Convert Tuples to Dictionary Python Convert string tuples to list tuples Python List of tuples to dictionary conversion Python Convert list of tuples to list of strings Python Convert list of strings to list of tuples Python Convert list elements to bi-tuples Python Convert list of tuples into digits Python Convert String to list of tuples Python Convert list of tuples into list Python Convert list of tuples to list of list Python Convert List of Dictionary to Tuple list Python Convert a list to dictionary Python Convert list of tuple into dictionary.

Chinmoy Lenka. Check out this Author's contributed articles. Load Comments.


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