176 lines
9.1 KiB
Markdown
176 lines
9.1 KiB
Markdown
---
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id: 587d7da9367417b2b2512b68
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title: Use the reduce Method to Analyze Data
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challengeType: 1
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videoUrl: ''
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localeTitle: Utilice el método de reducción para analizar datos
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---
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## Description
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<section id="description"> <code>Array.prototype.reduce()</code> , o simplemente <code>reduce()</code> , es la más general de todas las operaciones de matriz en JavaScript. Puede resolver casi cualquier problema de procesamiento de matrices utilizando el método de <code>reduce</code> . Este no es el caso con los métodos de <code>filter</code> y <code>map</code> , ya que no permiten la interacción entre dos elementos diferentes de la matriz. Por ejemplo, si desea comparar elementos de la matriz, o agregarlos juntos, el <code>filter</code> o el <code>map</code> no podrían procesarlo. El método de <code>reduce</code> permite formas más generales de procesamiento de matrices, y es posible mostrar que tanto el <code>filter</code> como el <code>map</code> pueden derivarse como una aplicación especial de <code>reduce</code> . Sin embargo, antes de que lleguemos allí, practiquemos <code>reduce</code> primero. </section>
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## Instructions
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<section id="instructions"> La lista de <code>watchList</code> variable contiene una serie de objetos con información sobre varias películas. Use <code>reduce</code> para encontrar la calificación promedio de IMDB de las películas <strong>dirigidas por Christopher Nolan</strong> . Recuerde de los desafíos anteriores cómo <code>filter</code> datos y <code>map</code> para obtener lo que necesita. Es posible que deba crear otras variables, pero guardar el promedio final en la variable <code>averageRating</code> . Tenga en cuenta que los valores de calificación se guardan como cadenas en el objeto y deben convertirse en números antes de que se utilicen en cualquier operación matemática. </section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: La variable <code>watchList</code> no debe cambiar.
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testString: 'assert(watchList[0].Title === "Inception" && watchList[4].Director == "James Cameron", "The <code>watchList</code> variable should not change.");'
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- text: Su código debe utilizar el método de <code>reduce</code> .
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testString: 'assert(code.match(/\.reduce/g), "Your code should use the <code>reduce</code> method.");'
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- text: La <code>averageRating</code> debe ser igual a 8.675.
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testString: 'assert(averageRating == 8.675, "The <code>averageRating</code> should equal 8.675.");'
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- text: Su código no debe utilizar un bucle <code>for</code> .
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testString: 'assert(!code.match(/for\s*?\(.*\)/g), "Your code should not use a <code>for</code> loop.");'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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// the global variable
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var watchList = [
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{
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"Title": "Inception",
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"Year": "2010",
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"Rated": "PG-13",
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"Released": "16 Jul 2010",
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"Runtime": "148 min",
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"Genre": "Action, Adventure, Crime",
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"Director": "Christopher Nolan",
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"Writer": "Christopher Nolan",
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"Actors": "Leonardo DiCaprio, Joseph Gordon-Levitt, Ellen Page, Tom Hardy",
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"Plot": "A thief, who steals corporate secrets through use of dream-sharing technology, is given the inverse task of planting an idea into the mind of a CEO.",
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"Language": "English, Japanese, French",
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"Country": "USA, UK",
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"Awards": "Won 4 Oscars. Another 143 wins & 198 nominations.",
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"Poster": "http://ia.media-imdb.com/images/M/MV5BMjAxMzY3NjcxNF5BMl5BanBnXkFtZTcwNTI5OTM0Mw@@._V1_SX300.jpg",
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"Metascore": "74",
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"imdbRating": "8.8",
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"imdbVotes": "1,446,708",
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"imdbID": "tt1375666",
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"Type": "movie",
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"Response": "True"
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},
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{
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"Title": "Interstellar",
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"Year": "2014",
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"Rated": "PG-13",
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"Released": "07 Nov 2014",
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"Runtime": "169 min",
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"Genre": "Adventure, Drama, Sci-Fi",
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"Director": "Christopher Nolan",
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"Writer": "Jonathan Nolan, Christopher Nolan",
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"Actors": "Ellen Burstyn, Matthew McConaughey, Mackenzie Foy, John Lithgow",
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"Plot": "A team of explorers travel through a wormhole in space in an attempt to ensure humanity's survival.",
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"Language": "English",
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"Country": "USA, UK",
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"Awards": "Won 1 Oscar. Another 39 wins & 132 nominations.",
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"Poster": "http://ia.media-imdb.com/images/M/MV5BMjIxNTU4MzY4MF5BMl5BanBnXkFtZTgwMzM4ODI3MjE@._V1_SX300.jpg",
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"Metascore": "74",
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"imdbRating": "8.6",
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"imdbVotes": "910,366",
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"imdbID": "tt0816692",
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"Type": "movie",
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"Response": "True"
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},
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{
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"Title": "The Dark Knight",
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"Year": "2008",
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"Rated": "PG-13",
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"Released": "18 Jul 2008",
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"Runtime": "152 min",
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"Genre": "Action, Adventure, Crime",
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"Director": "Christopher Nolan",
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"Writer": "Jonathan Nolan (screenplay), Christopher Nolan (screenplay), Christopher Nolan (story), David S. Goyer (story), Bob Kane (characters)",
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"Actors": "Christian Bale, Heath Ledger, Aaron Eckhart, Michael Caine",
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"Plot": "When the menace known as the Joker wreaks havoc and chaos on the people of Gotham, the caped crusader must come to terms with one of the greatest psychological tests of his ability to fight injustice.",
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"Language": "English, Mandarin",
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"Country": "USA, UK",
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"Awards": "Won 2 Oscars. Another 146 wins & 142 nominations.",
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"Poster": "http://ia.media-imdb.com/images/M/MV5BMTMxNTMwODM0NF5BMl5BanBnXkFtZTcwODAyMTk2Mw@@._V1_SX300.jpg",
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"Metascore": "82",
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"imdbRating": "9.0",
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"imdbVotes": "1,652,832",
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"imdbID": "tt0468569",
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"Type": "movie",
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"Response": "True"
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},
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{
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"Title": "Batman Begins",
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"Year": "2005",
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"Rated": "PG-13",
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"Released": "15 Jun 2005",
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"Runtime": "140 min",
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"Genre": "Action, Adventure",
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"Director": "Christopher Nolan",
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"Writer": "Bob Kane (characters), David S. Goyer (story), Christopher Nolan (screenplay), David S. Goyer (screenplay)",
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"Actors": "Christian Bale, Michael Caine, Liam Neeson, Katie Holmes",
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"Plot": "After training with his mentor, Batman begins his fight to free crime-ridden Gotham City from the corruption that Scarecrow and the League of Shadows have cast upon it.",
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"Language": "English, Urdu, Mandarin",
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"Country": "USA, UK",
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"Awards": "Nominated for 1 Oscar. Another 15 wins & 66 nominations.",
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"Poster": "http://ia.media-imdb.com/images/M/MV5BNTM3OTc0MzM2OV5BMl5BanBnXkFtZTYwNzUwMTI3._V1_SX300.jpg",
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"Metascore": "70",
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"imdbRating": "8.3",
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"imdbVotes": "972,584",
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"imdbID": "tt0372784",
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"Type": "movie",
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"Response": "True"
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},
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{
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"Title": "Avatar",
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"Year": "2009",
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"Rated": "PG-13",
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"Released": "18 Dec 2009",
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"Runtime": "162 min",
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"Genre": "Action, Adventure, Fantasy",
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"Director": "James Cameron",
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"Writer": "James Cameron",
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"Actors": "Sam Worthington, Zoe Saldana, Sigourney Weaver, Stephen Lang",
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"Plot": "A paraplegic marine dispatched to the moon Pandora on a unique mission becomes torn between following his orders and protecting the world he feels is his home.",
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"Language": "English, Spanish",
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"Country": "USA, UK",
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"Awards": "Won 3 Oscars. Another 80 wins & 121 nominations.",
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"Poster": "http://ia.media-imdb.com/images/M/MV5BMTYwOTEwNjAzMl5BMl5BanBnXkFtZTcwODc5MTUwMw@@._V1_SX300.jpg",
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"Metascore": "83",
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"imdbRating": "7.9",
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"imdbVotes": "876,575",
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"imdbID": "tt0499549",
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"Type": "movie",
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"Response": "True"
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}
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];
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// Add your code below this line
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var averageRating;
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// Add your code above this line
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console.log(averageRating);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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