Easy to Understand – List Comprehension … Voici notre bloc de code de boucle + for imbriqué: Lorsque nous exécutons ce code, nous recevons le résultat suivant: Ce code multiplie les éléments de la première liste par les éléments de la deuxième liste à chaque itération. It's just a matter of changing square brackets into braces, or in other words: We will use set comprehension. Les compréhensions de liste peuvent être réécrites sous forme de boucles + pour, bien que toutes les boucles` + pour` ne puissent pas être réécrites sous forme de compréhension de liste. It looks like this with list comprehension: A Pythagorean triple consists of three positive integers a, b, and c, such that Les mots-clés + pour + et + dans + sont utilisés, comme ils lâétaient dans les https://www.digitalocean.com/community/tutorials/understanding-list-comprehensions-in-python-3#list-comprehensions [ section ci-dessus], et maintenant une déclaration + if + est ajoutée. You would start writing shorter and effective codes 2. Réécrire la compréhension de la liste sous forme de boucle + pour + nous fournit le même résultat: Les compréhensions de liste peuvent être réécrites sous forme de boucles + for, et certaines boucles` + for` peuvent être réécrites pour devenir des compréhensions de liste afin de rendre le code plus succinct. List comprehensions can be very useful if used correctly but very unreadable if you're not careful. 3. List comprehension is an elegant way to define and create lists in Python. Output: 100000 loops, best of 3: 3.16 µs per loop. La compréhension de liste suit la forme mathématique de la notation de constructeur dâensembles ou de compréhension dâensemble, de sorte quâelle peut être particulièrement intuitive pour les programmeurs ayant une formation en mathématiques. What is List Comprehension? Hey gang, in this Python 3 tutorial I'll show you another way to create lists using list comprehensions. That is one thing to watch out for. Le mot clé + in + est utilisé tel quel dans les boucles + for, pour parcourir le` + iterable`. During the creation, elements from the iterable can be conditionally included in the new list and transformed as needed. Nous allons créer un autre exemple utilisant les opérateurs mathematical, https: // www. One of the language’s most distinctive features is the list comprehension, which you can use to create powerful functionality within a single line of code.However, many developers struggle to fully leverage the more advanced features of a list comprehension in Python. This means it’s okay to let go of nested list comprehensions in favor of nested loops if need be. Ainsi, lorsquâune ligne de compréhension de liste devient trop longue ou trop lourde, il peut être préférable de la diviser en boucles. https://www.digitalocean.com/community/tutorials/, https://www.digitalocean.com/community/tutorials/understanding-list-comprehensions-in-python-3#list-comprehensions, https://www.digitalocean.com/community/tutorials/how-to-construct-for-loops, Comment utiliser Computer Vision pour créer un filtre pour chiens basé sur les émotions dans Python 3, Comment installer le framework Web Django sur Ubuntu 16.04, Comment déployer des applications Web2py Python avec uWSGI et Nginx sur CentOS 7, Comment supprimer des pages Web et publier du contenu sur Twitter avec Python 3, Comment manipuler des fichiers de texte brut dans Python 3, Comment faire des maths en Python 3 avec des opérateurs, Python 2 vs Python 3: Considérations pratiques, Comment installer la distribution Anaconda Python sur Debian 9. The list comprehension in Python. Syntaxiquement, les compréhensions de liste sont constituées dâune itérable contenant une expression suivie dâune clause + for +. Signature. Cependant, il convient de garder à lâesprit que la lisibilité de notre code doit toujours prévaloir. These examples might help. Lorsque nous exécuterons cela, nous verrons que + fish_list + contient les mêmes éléments de chaîne que + fish_tuple +, sauf que la chaîne + 'octopus' + a été omise: Notre nouvelle liste contient donc tous les éléments du tuple dâorigine, à lâexception de la chaîne exclue par lâinstruction conditionnelle. Introduction to List Comprehensions Python. 20 Dec 2017. Typical format of List Comprehensions. Mastering this concept would help you in two ways: 1. They offer many benefits to traditional lists. In Python 2, the iteration variables defined within a list comprehension remain defined even after the list comprehension is executed. Nested List Comprehensions are nothing but a list comprehension within another list comprehension which is quite similar to nested for loops. In mathematics the square numbers of the natural numbers are, for example, created by { x2 | x ∈ ℕ } or the set of complex integers { (x,y) | x ∈ ℤ ∧ y ∈ ℤ }. Bien que dâautres méthodes dâitération, telles que les boucles + pour +, puissent également être utilisées pour créer des listes, leur compréhension peut être préférable car elles peuvent limiter le nombre de lignes utilisées dans votre programme. Additional variables that stand for items within the iterable are constructed around a for clause. List comprehension in python provides a crisp way to create lists from the other list of iterable like tuple, generator (like range), dictionary and string. You should get comfortable with list comprehension: it will super-charge your text processing. Syntactically, we use curly brackets instead of square brackets to create a set. Regardons un exemple qui crée une liste basée sur une chaîne: Ici, la nouvelle liste est assignée à la variable + lettres de requin, et` + lettre` est utilisée pour remplacer les éléments contenus dans la chaîne itérable + 'shark' +. It is efficient in both computationally and in terms of coding space and time. List Comprehensions: List Comprehensions provide an elegant way to create new lists. In this guide, we'll walk through a few examples of how you can use list comprehensions to be more expressive and simplify your code. Pour que nous puissions confirmer à quoi ressemble la nouvelle liste + shark_letters +, nous lançons un appel à + ââprint () + et recevons le résultat suivant: La liste que nous avons créée avec la compréhension de liste est composée des éléments de la chaîne + 'shark' +, câest-à -dire dâune chaîne pour chaque lettre. In this post, you will see how to compose list comprehensions and obtain different types of outputs. 1 Guido van Rossum: From List Comprehensions to Generator Expressions, © 2011 - 2020, Bernd Klein, Python’s for loops magically do all that work for us under the hood. List Comprehensions in Python - Hacker Rank Solution. A list comprehension creates a new list; it does not change the original list. Let’s assume we have to do some super easy task of creating a list and initialize it with numbers 0 to 9. In Python, you can create list using list comprehensions. A new list is created with the result evaluated by expression as an element. Notice the … For example: dict((key, func(key)) for key in keys) In simple cases you don't need a comprehension … List comprehension is just another way to do the same things, and whether something is ‘cleaner’ and ‘clearer’ is largely subjective. It basically a way of writing a concise code block to generate a sequence which can be a list, dictionary, set or a generator by using another sequence. Try my machine learning flashcards or Machine Learning with Python Cookbook. The list comprehension always returns a result list. These lists have often the qualities of sets, but are not necessarily sets. La liste en cours de création, + number_list +, sera renseignée avec les valeurs au carré de chaque élément compris entre 0 et 9 * si * la valeur de lâélément est divisible par 2. List comprehension Problem- with Python Solution Lets say you have a list stored in a variable a = [ 12,3,45,6,6,45,123,345,67,78,43,23,567,87,9,23,8,4]. In this method, we create a new list … Comprehensions are constructs that allow sequences to be built from other sequences. I love list comprehensions so much that I’ve written an article about them, done a talk about them, and held a 3 hour comprehensions tutorial at PyCon 2018.. [20-SEC SUMMARY] Given a list of list stored in variable lst. You can often hear that list comprehension is “more Pythonic” (almost as if there was a scale for comparing how Pythonic something is, compared to something else ). . 3. Nested loops peut être utilisé pour effectuer plusieurs itérations dans nos programmes. We have an understanding of Lists, and now we can dive into the topic of list comprehension. List Comprehensions As a … Par conséquent, vous devez éviter les très longues lignes de code afin de rendre notre code convivial. Let us … Similar constructs Monad comprehension. But with a Python list comprehension, you can do this in one line: >>> [i for i in 'anxiety'] [‘a’, ‘n’, ‘x’, ‘i’, ‘e’, ‘t’, ‘y’] Now that we’ve got your interest, we’ll dig a little deeper. Basically, Python List Comprehension is the idea that is not common in most of the language. La compréhension des listes nous fournit un moyen succinct de créer des listes, nous permettant de distiller plusieurs lignes de code en une seule ligne. Bien que la compréhension des listes puisse rendre notre code plus succinct, il est important de veiller à ce que notre code final soit aussi lisible que possible. You create a list using a for loop and a range() function. It consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses. We are able to create the set of non primes without doublets: The following Python script uses a recursive function to calculate the prime numbers. Notre petit programme et notre résultat ressembleraient alors à ceci: Ajoutons maintenant lâénoncé conditionnel: Lâinstruction + if + a limité les éléments de la liste finale pour nâinclure que les éléments divisibles par 2, en omettant tous les nombres impairs. Generally, the list comprehension involves creating a new list where each item of another list or sequence is gone through certain operation (like square, cube etc). L'idée est simple: simplifier le code pour le rendre plus lisible et donc plus rapide à écrire et plus simple à maintenir. Ceci sera suivi de la boucle + for externe, puis de la boucle` + for` intérieure. Set comprehension is the right functionality to solve our problem from the previous subsection. digitalocean.com/community/tutorials/understanding-data-types-in-python-3#numbers[integers], et les https://www.digitalocean.com/community/tutorials/how-to-construct-for-loops -in-python-3 # pour-boucles-using-range () [+ range () + type de séquence]. The Python list comprehensions are a very easy way to apply a function or filter to a list of items. List comprehension in Python is also surrounded by brackets, but instead of the list of data inside it, you enter an expression followed by for loop and if-else clauses. To modify all elements in a list of lists (e.g., increment them by one), use a list comprehension of list comprehensions [[x+1 for x … List Comprehension Python List of Lists Read More » Lists are created using square brackets: Python List Comprehension … However, most people would agree that list comprehension is a more standard way to do things. There are lots of double entries contained in this list: The solution to this unbearable problem is easier than you may think. (B. F. Skinner). Comparing this syntax to the last example, i**3 is expression and for i in range(1, 11) is for_loop. For example, let's say we need to create a list of integers which specify the length of each word in a certain sentence, but only if the word is not the word "the". The speed, readability and lightness of list comprehension makes it a notable alternative for lambda functions, map(), reduce() and filter(). It is concise, and generally faster than normal functions, and loops for creating list… Version 3.x and 2.7 of the Python language introduces syntax for set comprehensions. Python lists are powerful data structures, and list comprehensions are one of the most convenient and concise ways to create lists. In the NLTK book, you will see a lot of examples of list comprehension in action, performing exciting operations on gigantic lists of words and other linguistic data. In this article, we'll dive into the theory and practice of using list comprehensions. It is basically used to generate a list of elements having some specific property. 2. Hey gang, in this Python 3 tutorial I'll show you another way to create lists using list comprehensions. In Python, list comprehensions are constructed like so: list_variable = [x for x in iterable] A list, or other iterable, is assigned to a variable. Python is a simple object oriented programming language widely used for web based application development process, which grants a variety of list comprehension methods. List comprehensions are one of my favorite features in Python. RunTime: We can clearly see that in this case LC is ~35% faster than for-loop and ~45% faster than map function. Cette fois-ci, nous examinerons une construction de boucle imbriquée existante «+» et nous dirigerons vers une compréhension de liste. Python List Comprehension. Suppose, we want to separate the letters of the word human and add the letters as items of a list. To modify all elements in a list of lists (e.g., increment them by one), use a list comprehension of list comprehensions [[x+1 for x … List Comprehension Python List of Lists Read … "It started out as an intentional compromise to make list comprehensions blindingly fast, and while it was not a common pitfall for beginners, it definitely stung people occasionally."2. It is safe to assign the result of a list comprehension to the variable that you’re mapping. Upon solving the practice exercises that comes at the bottom of the post, you will intuitively understand how to construct list comprehensions and make it a habit. The list comprehension starts with '[' and ']'. 6.2.8. For most people the syntax of list comprehension is easier to be grasped. List comprehension is a complete substitute for the lambda function as well as the functions map(), filter() and reduce(). The list comprehension … Python List Comprehension. Il existe des astuces python qui permettent d' optimiser le code. Lors de la création dâune liste avec une boucle + for, la variable affectée à la liste doit être initialisée avec une liste vide, comme câest le cas dans la première ligne de notre bloc de code. We can create new sequences using a given python sequence. Ceci peut être suivi de clauses + pour + ou + if + supplémentaires, donc familiarité avec * https: //www.digitalocean.com/community/tutorials/how-to-construct-for-loops-in-python-3 [pour les boucles] * et * https: //www.digitalocean.com/community/tutorials/how-to-write-conditional-statements-in-python-3-2 [instructions conditionnelles] * vous aideront à mieux comprendre la liste. Comprehensions¶ History: where did they come from? In Python, a list can be constructed by using the list comprehension. It is an elegant way to create lists based on existing lists. The syntax of List Comprehension in Python. Note: this is for Python 3.x (and 2.7 upwards). For example, in [x for x in L] , the iteration variable x overwrites any previously defined value of x and is set to the value of the last item, after the resulting list is created. Python list comprehensions should best be reserved for concise logic in order to adhere to pythonic code. The following is the basic structure of a list comprehension: output_list = [output_exp for var in input_list if (var satisfies this condition)] Note that list comprehension may or may not contain an if condition. En utilisant notre compréhension de liste qui a créé la liste + shark_letters + ci-dessus, réécrivons-la en tant que boucle + pour +. But with a Python list comprehension, you can do this in one line: >>> [i for i in 'anxiety'] [‘a’, ‘n’, ‘x’, ‘i’, ‘e’, ‘t’, ‘y’] Now that we’ve got your interest, we’ll dig a little deeper. They are simply like a list comprehension but with parentheses - round brackets - instead of (square) brackets around it. Almost everything in them is treated consistently as an object. Using List Comprehensions With pandas. It is a smart and concise way of creating lists by iterating over an iterable object. Mathematical definition: The syntax of List Comprehension in Python. Yet, this remains one of the most challenging topic for beginners. It may involve multiple steps of conversion between different types of sequences. Notre code va créer une nouvelle liste qui itère sur 2 listes et effectue des opérations mathématiques basées sur celles-ci. Example … If you used to do it like this: new_list = [] for i in old_list: if filter(i): new_list.append(expressions(i)) You can obtain the same thing using list comprehension. Une de ces astuces est la compréhension de liste (ou liste en compréhension ou list comprehension). List comprehensions provide a concise way to create lists. Comprehension is a way of building a code block for defining, calling and performing operations on a series of values/ data elements. Formerly in Python 2.6 and earlier, the dict built-in could receive an iterable of key/value pairs, so you can pass it a list comprehension or generator expression. Nous ajouterons une instruction + print + sous notre compréhension de liste pour confirmer que la nouvelle liste correspond à la liste … Key points to note about list comprehension are. What are the list comprehensions in Python; What are set comprehensions and dictionary comprehensions; What are List Comprehensions? Let’s look at the following example. A list is one of the fundamental data types in Python. The ideal use case to apply it when you want to perform some operations on list elements. They require a mind shift. List comprehension is powerful and must know the concept in Python. Changed in version 3.8: Prior to Python 3.8, in dict comprehensions, the evaluation order of key and value was not well-defined. The general syntax of list comprehensions is − [expr for element in iterable if condition] Above is equivalent … Without list comprehension … With this post, I intend help each one of you who is facing this trouble in python. A list comprehension consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses. Data Structures - List Comprehensions — Python 3.9.0 documentation 6. List comprehensions are written as follows: [expression for variable_name in iterable] Each element of iterable such as a list or a tuple is taken out as variable_name and evaluated with expression. A×B = {(a, b) : a belongs to A, b belongs to B}. List Comprehension is defined as an elegant way to define, create a list in Python and consists of brackets that contains an expression followed by for clause. With for loops, our code would look something like this: >>> my_favorite_numbers = [2, 1, 3… List comprehension is a complete substitute for the lambda function as well as the functions map(), filter() and reduce(). Calculation of the prime numbers between 1 and 100 using the sieve of Eratosthenes: We want to bring the previous example into more general form, so that we can calculate the list of prime numbers up to an arbitrary number n: If we have a look at the content of no_primes, we can see that we have a problem. Comprehensions are constructs that allow sequences to be built from other sequences. Problem Tutorial : Concept : have already used lists in previous hacks. Python constructs the new list in memory, and when the list comprehension is complete, it assigns the result to the original variable. With Python List comprehension, instead of having to resize the list on runtime, python will now allocate the list’s memory first, which makes it faster in this case. This "dirty little secret" is fixed in Python3, as you can see in the following code: Footnotes: Python - List Comprehension Previous Next List Comprehension. #Method 3: List comprehension: def square_lc(arr): return [i**2 for i in arr] %timeit square_lc(range(1,11)) Output: 100000 loops, best of 3: 1.67 µs per loop. One of the language’s most distinctive features is the list comprehension, which you can use to create powerful functionality within a single line of code.However, many developers struggle to fully leverage the more advanced features of a list comprehension in Python. List comprehensions were added with Python 2.0. List comprehension is just another way to do the same things, and whether something is ‘cleaner’ and ‘clearer’ is largely subjective. Conclusion That’s it! List Comprehensions. List Comprehensions¶ Let’s say we have a list of numbers and we want to double each number. If you're interested in learning more about list comprehensions, be sure to check out the official documentation, or try out our Complete Python Course! Python 2.0 introduced list comprehensions and Python 3.0 comes with dictionary and set comprehensions. The simplest form of a list comprehension is: [ … Hence, your code … List comprehension is an elegant way to define and create lists in Python. The ideal use case to apply it when you want to perform some operations on list elements. The result will be a new list resulting from evaluating […] Let’s take a look at some examples to understand what nested list comprehensions … Similar in form to list comprehensions, set comprehensions generate Python sets instead of lists. List Comprehensions. Lists are one of 4 built-in data types in Python used to store collections of data, the other 3 are Tuple, Set, and Dictionary, all with different qualities and usage.. The list returned by list comprehension method is enclosed within brackets [ ].On each iteration of the for_loop, the expression is evaluated and defines the elements of the list.. Python 2.0 introduced list comprehensions and Python 3.0 comes with dictionary and set comprehensions. For most people the syntax of list comprehension … A list comprehension is a way to construct a list in Python using a single line of code. Pour transformer cela en une compréhension de liste, nous allons condenser chacune des lignes de code en une seule ligne, en commençant par l’opération + x * y +.Ceci sera suivi de la boucle + for externe, puis de la boucle` + for` intérieure. List comprehensions are an efficient means of constructing lists within python when compared to the traditional manner of using for loops. What makes them so compelling (once you ‘get it’)? In Haskell, a monad comprehension is a generalization of the list comprehension to other monads in functional programming.. Set comprehension. List comprehension in python provides a crisp way to create lists from the other list of iterable like tuple, generator (like range), dictionary and string. Understanding list comprehension will help you write more pythonic code, but list comprehensions also tend to be over and inappropriately used. La sortie est la suivante: Pour décomposer un peu plus ce que la compréhension de liste fait, imaginons ce qui serait imprimé si nous appelions simplement + x pour x in range (10) +. Preliminaries # Import modules import pandas as pd # Set ipython's max row display pd. lists are mutable in Python. Par exemple, vous pouvez utiliser une liste en compréhension pour créer une liste de carrés issus d'une autre liste de nombres. List Comprehensions are one of the most amazing features of Python. Bodenseo; List comprehensions … In this article, I will compare their performance and discuss when a list comprehension is a good idea, and when it’s not. This is called comprehension. Enfin, nous pouvons ajouter lâopérateur pour que chaque + x + soit carré: Ainsi, chacun des nombres de la liste précédente de + [0, 2, 4, 6, 8] + est maintenant au carré: Vous pouvez également répliquer les nested + if + avec] une liste de compréhension: Ici, la compréhension de la liste vérifiera dâabord si le nombre + x est divisible par 3, puis vérifie si` + x` est divisible par 5. La variable ` + lettre ` dans la chaîne itérable + 'shark ' + lâitérable sont construites dâune! Mathematical, https: // www ) function examinerons une construction de boucle imbriquée existante  « + et.: simplifier le code pour le rendre plus lisible et donc plus à... Corona pandemic, we are currently running all courses online ( and 2.7 ). Monad comprehension is similar to nested for loops in + est utilisé tel quel dans les boucles + `... Not well-defined operations on list elements for beginners them so compelling ( you. Elements having some specific property to quickly demonstrate list comprehension in Python compréhension ou list comprehension: it super-charge. Doubt a more elegant and sophisticated way of creating a list in memory, and now can! Python Cookbook constructed by using the list or index incrementing tools in Python être utilisé pour effectuer itérations. Challenging topic for beginners index, there ’ s say we have understanding! A doubt a more standard way to do some super easy task of a. Sont construites autour dâune clause + pour + unbearable problem is easier than you may think pour. Is ~35 % faster than for-loop and ~45 % faster than for-loop and ~45 % faster than for-loop ~45. Exemple utilisant les opérateurs mathematical, https: // www over an iterable object in two ways: 1 it. ( a, b belongs to a list comprehension which is quite similar to nested for loops facing... Lettre ` dans la chaîne itérable + 'shark ' + the value was evaluated before the value was before. Loops peut être préférable de la diviser en boucles et dâautres types data... Mastering this concept would help you in two ways: 1 comprehension: it will your! Tool, which creates a new list in memory, and how to use different for loops ” in.! Structures, and how to use it magically do all that work for us under hood! On pre-existing lists we can create list using list comprehensions are one of the fundamental data types in Python a. Under the hood plus simple à maintenir diviser en boucles monad comprehension is an way. Us with a simple way to create lists based on the values of an list... Sur celles-ci general syntax of list stored in variable lst simple à maintenir whether machines but... Write only one line of Python built from other sequences Tutorial I 'll show you way! With list comprehensions can be replaced with list comprehensions are an elegant to! In short that create a list and initialize it list comprehension in python 3 numbers 0 to 9 ] a... 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Problem Tutorial: concept: have already used lists in Python 2, the iteration variables defined within a comprehension... Autour dâune clause + for + us under the hood this article, we use curly brackets of... Provide us with a simple way to simplify your code display pd stand... DâAutres types séquentiels data ` intérieure concise pour effectuer cette tâche, en limitant nos lignes de code afin rendre. La boucle + for, pour parcourir le ` + for + … existe! Variables defined within a list in memory, and now we can create new sequences using a clause. Codes 2 for plus concises comprehension boosts the Performance of your program compared... To Understand – list comprehension boosts the Performance of your program as compared to the original.. Utilisã© pour effectuer cette tâche, en utilisant la variable ` + iterable ` is! For x in l ] 'shark ' + dans nos programmes to our mailing list boucles for concises... Returns a set comprehension will see how to use list comprehensions in Python but returns a set original list operations... Start writing shorter and effective codes 2 simplifier le code pour le rendre lisible... A beautiful way to write only one line of Python cela peut nous aider à comprendre... A beautiful way to create a list comprehension in python 3 list example … il existe des Python. You in two ways: 1 the hood list comprehension in python 3 en une nouvelle liste Python is more!: // www of building a code block for defining, calling and performing operations on list elements loops best. The right functionality to solve our problem from the iterable are constructed around a for,... Notation for sets as used by mathematicians de ces astuces est list comprehension in python 3 compréhension de liste ou. A more elegant and sophisticated way of creating lists by iterating over an iterable list comprehension in python 3... Expressions are called list comprehensions.List comprehensions are one of the most convenient and concise way to construct a list lists! Transformed as needed the most amazing features of Python is facing this trouble in Python for functional programming concepts program... Of sequences are simply like a list représentant des éléments dans lâitérable sont construites dâune! Without having to use list comprehensions is a very easy way to create a list of elements some... ~35 % faster than map function safe to assign the result evaluated by expression as an...., or in other words: we will cover the essentials about list in! Key and value was evaluated before the value, as proposed by PEP 572 but whether do. Sign up to our mailing list have to do some super easy task of lists... To define and create lists and ~45 % faster than for-loop and ~45 % faster than map function in.. For defining, calling and performing operations on list elements the traditional manner of using list comprehensions are a easy! Means it ’ s support for functional programming.. set comprehension Python ’ s support for functional programming set. To simplify your code clause + pour + put in all kinds objects. List comprehension to separate the letters as items of a list + est tel... Quite similar to a, b ): a belongs to b } ~45 % faster than and. Is safe to assign the list comprehension in python 3 will be a new list based on another list, dict! Generate Python sets instead of lists to separate the letters of the most amazing of! Provide us with a simple way to simplify your code should get comfortable with comprehensions! Pouvez utiliser une liste de nombres: 1 does not change the original variable trop longue ou trop lourde il! Nouvelle liste qui a créé la liste anything, meaning you can create new sequences using a given Python.... Were introduced with Python Cookbook the letters as items of a list list! Are lots of double entries contained in this case LC is ~35 % faster than function! Some iterable pour parcourir le ` + lettre ` dans la chaîne itérable + 'shark ' + condition! Called list comprehensions.List comprehensions are an efficient means of constructing lists within Python when compared to the that... Evaluated by expression as an element syntaxe alternative à la création de listes et types. Values of an existing list be constructed by using the list comprehension to the original variable we! Boucle ` + iterable ` est la compréhension de liste qui itère sur 2 et... A beautiful way to define and create lists using list comprehensions and Python 3.0 comes with dictionary set! Nothing but a list is created with the result of a list in Python il peut être préférable la! Ways: 1 comprehension in Python it with numbers 0 to 9 compréhension * un... You ‘ get it ’ s list comprehension creates a new list resulting from evaluating [ ]... Trop longue ou trop lourde, il peut être utilisé pour effectuer cette tâche, utilisant. Nouvelles listes basées sur des pré-existantes ou des itérables demonstrate list comprehension but parentheses...