Question 225569 in Javascript Question posted in
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Javascript – iterate through array of objects and change apperence of another array inside

How can i edit an array inside an object?
My array contains a string, but i wanted the string to be split up via .split("") or another method.
This is how it looks at the moment:

line1_x = [
{"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
{"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
{"id": 3, "topic_no": 453, "keywords": ["[Keyword1, Keyword2, Keyword3]"] }
]

In this case, the brackets are part of the string. I would remove them via .replaceAll() or regex, i guess?
What i would like to archieve is following:

line1_x = [
{"id": 1, "topic_no": 451, "keywords": ["Keyword1", "Keyword2", "Keyword3"] },
{"id": 2, "topic_no": 452, "keywords": ["Keyword1", "Keyword2", "Keyword3"] },
{"id": 3, "topic_no": 453, "keywords": ["Keyword1", "Keyword2", "Keyword3"] }
]

I assume i need to iterate through the line1_x via a normal loop and use the .split("") method?

Tags:

4

Answers


  1. 0

    To edit the arrays inside the objects and split the strings into separate keywords, you can loop through the array and use the map function to update the keywords property. Here’s a step-by-step explanation of how you can achieve this in JavaScript:

    // Your original array of objects
const line1_x = [
  {"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"]},
  {"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"]},
  {"id": 3, "topic_no": 453, "keywords": ["[Keyword1, Keyword2, Keyword3]"]}
];

// Define a function to split the string and remove the square brackets
function splitAndTrimKeywords(str) {
  return str.split(", ").map(keyword => keyword.replace("[", "").replace("]", "").trim());
}

// Loop through the array and update the 'keywords' property for each object
const updatedLine1_x = line1_x.map(obj => {
  return {
    ...obj,
    keywords: splitAndTrimKeywords(obj.keywords[0]) // Assuming there's always only one string in the 'keywords' array
  };
});

// Now 'updatedLine1_x' contains the objects with split keywords
console.log(updatedLine1_x);
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  2. 0

    Here is a simple solution. Note that I came to the conclusion that your keywords will always have one member.

    const line1_x = [
  {"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 3, "topic_no": 453, "keywords": ["[Keyword1, Keyword2, Keyword3]"] }
];

function formatKeywords(line) {
  return line.map(row => {
    row.keywords = row.keywords[0].replaceAll(/[[]']+/g, "").split(", ");
    return row;
  });
}

console.log(formatKeywords(line1_x));
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  3. 0

    I propose a regex solution:

    b[^][,]+b

    Matching everything but not ,, [ or ] sitting between two word boundaries.

    const line1_x = [
  {"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 3, "topic_no": 453, "keywords": ["[Keyword1,Keyword2, Some Keyword3 ]"] }
];

const output = line1_x.map(({ keywords, ...rest }) => ({ 
  ...rest,
  keywords: keywords[0].match(/b[^][,]+b/g)
}));

console.log(output);
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  4. 0

    If your keywords consist of alphanumeric chars only you could use a simple regex /w+/g to match all keywords. Also note that using rest syntax involves iterators which are slow, so if the object structure is known and performance is important I suggest to compose object manually.

    Also it’s not clear whether you want to get a new array or modify the existing one.

    To create a new array (pure approach):

    const result = line1_x.map(({id, topic_no, keywords:[kw]}) => ({
  id, topic_no, keywords: kw.match(/w+/g)
}));

console.log(result);
    <script>
const line1_x = [
{"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
{"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
{"id": 3, "topic_no": 453, "keywords": ["[Keyword1, Keyword2, Keyword3]"] }
]
</script>

    And the benchmark:

    enter image description here

    <script benchmark data-count="300000">
const line1_x = [
  {"id": 1, "topic_no": 451, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 2, "topic_no": 452, "keywords": ["[Keyword1, Keyword2, Keyword3]"] },
  {"id": 3, "topic_no": 453, "keywords": ["[Keyword1, Keyword2, Keyword3]"] }
]

// @benchmark Hao Wu
line1_x.map(({ keywords, ...rest }) => ({ 
  ...rest,
  keywords: keywords[0].match(/b[^][,]+b/g)
}));

// @benchmark Thomas (in-place)
 line1_x.map(row => {
    row.keywords = row.keywords[0].replaceAll(/[[]']+/g, "").split(", ");
    return row;
  });

// @benchmark Alexander
line1_x.map(({id, topic_no, keywords:[kw]}) => ({
      id, topic_no, keywords: kw.match(/w+/g)
    }));

// @benchmark Alexander (in-place)
line1_x.forEach(item => item.keywords = item.keywords[0].match(/w+/g));
line1_x;

</script>
<script src="https://cdn.jsdelivr.net/gh/silentmantra/benchmark/loader.js"></script>
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