शैडोइंग अभ्यास: Array Map in 100 Seconds - वीडियो के साथ अंग्रेजी बोलना सीखें

पाठ बनाया जा रहा है...
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ArrayMap.
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Create a new array by calling a function on every element in a different array.
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Imagine we have an array of squares.
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We can call a function on every single one of those
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squares using map to convert it to a new array of circles.
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In other words, it's just a loop, where the goal of that loop is to create a new array.
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In our code, let's start with an array of objects that contain some user data.
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Our goal is to take this array of objects
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and convert it to an array of strings that only contain the user names.
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You could do this imperatively by creating a new empty array, then use a for loop to push each individual username to the new array.
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Notice how we're using statements to change the app's state.
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This is known as imperative programming.
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Map on the other hand is declarative and describes how to create this new array using a function.
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The new array is equal to the original array mapped to a function.
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The function is passed as an argument to map, and it's called on every element in the original array.
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The function has access to the current element in the loop as well as its index.
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In the body of the function, your job is to compute a new value and then return it.
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And we've now solved the same problem we did with the for loop, but with less code and without mutating the internal state.
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If you're a ReactJS user, you'll often see Map used to take some initial data and then map it to JSX for the actual UI.
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Or maybe you need these usernames to do something asynchronously like fetch additional data from the database.
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You could do that by mapping them all to an array of promises, then running them concurrently with promise.all.
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One anti-pattern to be aware of with map is
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that you should only use it if you plan on using the new array.
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If you just need to run a loop, consider for each, or a regular for loop instead.
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This has been ArrayMap in 100 seconds, thanks for watching, and I will see you in the next one.

Vocabulary and speaking notes for this lesson

This video has 25 sentences and 372 words to shadow. The speech runs for 1:39. The speaker talks fast, about 227 words per minute, so expect linked and reduced sounds. Only 81% of the words are among the 3,000 most common in English, so the vocabulary is demanding.

Key vocabulary in this video

15 less common words from the video, with pronunciation and meaning:

  • array /əˈɹeɪ/ (noun) — Clothing and ornamentation; raiment.
  • loop /luːp/ (noun) — A length of thread, line or rope that is doubled over to make an opening.
  • element /ˈɛləmənt/ (noun) — One of the simplest or essential parts or principles of which anything consists, or upon which the constitution or fundamental powers of anything are based.
  • convert /kənˈvɝt/ (verb) — To transform or change (something) into another form, substance, state, or product.
  • username (noun) — A name or string of characters used as a person's identification on an individual computer system.
  • solve /sɒlv/ (verb) — To find an answer or solution to a problem or question; to work out.
  • string /stɹɪŋ/ (noun) — A long, thin and flexible structure made from threads twisted together.
  • database /ˈdeɪtəˌbeɪs/ (noun) — A collection of (usually) organized information in a regular structure, usually but not necessarily in a machine-readable format accessible by a computer.
  • imperative /ɪmˈpɛɹ.ə.tɪv/ (adjective) — Essential; crucial; extremely important.
  • fetch /fɛt͡ʃ/ (verb) — To retrieve; to bear towards; to go and get.
  • asynchronously (adverb) — In an asynchronous manner.
  • compute /kəmˈpjuːt/ (verb) — To reckon, calculate.
  • concurrently (adverb) — In a concurrent manner; at the same time.
  • declarative /dɪˈklæɹ.ə.tɪv/ (adjective) — Serving to declare; having the quality of a declaration.
  • imperatively (adverb) — In an imperative manner.

Phrasal verbs you will hear

  • call on (verb) — To visit (a person); to pay a call to.
  • plan on (verb) — To expect; to anticipate future actions based on.

Pronunciation to watch

The speaker uses 4 contractions and reduced forms, such as we're, we've, you'll. Say them the short way, as you hear them.

  • Long words — get the stress right: imperative /ɪmˈpɛɹ.ə.tɪv/, declarative /dɪˈklæɹ.ə.tɪv/

How to practise with this video

  1. Listen to the whole video once without speaking and note the words you do not know.
  2. Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
  3. Record yourself and compare with the original, paying attention to words like array, loop, element.

इस वीडियो का व्याकरण

वक्ता जिन संरचनाओं का सबसे अधिक प्रयोग करता है, वीडियो के असली शब्दों के साथ:

संरचनावीडियो में
Present perfect have/has + past participle — बीता हुआ काम जिसका असर अभी भी हैwe've now solved · has been
Passive voice be + past participle — ज़ोर इस पर कि क्या होता है, न कि कौन करता हैis known · is passed

शैडोइंग तकनीक क्या है?

शैडोइंग (Shadowing) एक विज्ञान-समर्थित भाषा सीखने की तकनीक है जो मूल रूप से पेशेवर दुभाषिया प्रशिक्षण के लिए विकसित की गई थी। विधि सरल लेकिन शक्तिशाली है: आप मूल अंग्रेज़ी ऑडियो सुनते हैं और तुरंत इसे ज़ोर से दोहराते हैं — जैसे वक्ता की छाया 1-2 सेकंड की देरी से। शोध से पता चलता है कि यह उच्चारण सटीकता, स्वर, लय, जुड़ी हुई ध्वनियाँ, सुनने की समझ और बोलने की प्रवाहशीलता में काफ़ी सुधार करता है।

शैडोइंग तकनीक: पूरी चरण-दर-चरण गाइड पढ़ें →