Author: John Au-Yeung

Web developer specializing in React, Vue, and front end development.

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JavaScript Answers

How to detect support for VML or SVG in a browser with JavaScript?

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Sometimes, we want to detect support for VML or SVG in a browser with JavaScript.

In this article, we’ll look at how to detect support for VML or SVG in a browser with JavaScript.

How to detect support for VML or SVG in a browser with JavaScript?

To detect support for VML or SVG in a browser with JavaScript, we can use the document.implementation.hasFeature method.

For instance, we write:

document.implementation.hasFeature("http://www.w3.org/TR/SVG11/feature#Shape", "1.0")

to detect SVG support in the browser.

If it returns true, then it’s supported.

Conclusion

To detect support for VML or SVG in a browser with JavaScript, we can use the document.implementation.hasFeature method.

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JavaScript Answers

How to paginate a JavaScript array?

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Sometimes, we want to paginate a JavaScript array.

In this article, we’ll look at how to paginate a JavaScript array.

How to paginate a JavaScript array?

To paginate a JavaScript array, we can use the JavaScript array’s slice method.

For instance, we write:

const paginate = (array, pageSize, pageNumber) => {
  return array.slice((pageNumber - 1) * pageSize, pageNumber * pageSize);
}

console.log(paginate([1, 2, 3, 4, 5, 6], 2, 2));
console.log(paginate([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 4, 1));

to create the paginate function that takes the array we want to pagination and the pageSize and pageNumber.

In the function, we call array.slice to return the elements that should be in the given pageNumber given the pageSize.

We pass in (pageNumber - 1) * pageSize as the start index and pageNumber * pageSize as the end index.

Therefore, from the console log, we get [3, 4] and [1, 2, 3, 4] respectively.

Conclusion

To paginate a JavaScript array, we can use the JavaScript array’s slice method.

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Python Answers

How to pad zeroes to a string with Python?

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Sometimes, we want to pad zeroes to a string with Python.

In this article, we’ll look at how to pad zeroes to a string with Python.

How to pad zeroes to a string with Python?

To pad zeroes to a string with Python, we can use the string’s zfill method.

For instance, we write:

n = '5'
print(n.zfill(3))

We call zfill with 3 to pad the string with 0’s before the number to make it 3 digits long.

Therefore, the print function should print '005'.

Conclusion

To pad zeroes to a string with Python, we can use the string’s zfill method.

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Python Answers

How to check if a string is a number with Python?

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Sometimes, we want to check if a string is a number with Python.

In this article, we’ll look at how to check if a string is a number with Python.

How to check if a string is a number with Python?

To check if a string is a number with Python, we can use the string’s isdigit method.

For instance, we write:

a = "03523"
print(a.isdigit())

b = "03523abc"
print(b.isdigit())

We call isdigit on a, which is a number string, so the first print call should print True.

Then we call isdigit on b, which isn’t a number string, so the 2nd print call should print False.

Conclusion

To check if a string is a number with Python, we can use the string’s isdigit method.

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Python Answers

How to append to a file with Python?

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Sometimes, we want to append to a file with Python.

In this article, we’ll look at how to append to a file with Python.

How to append to a file with Python?

To append to a file with Python, we can open the file with open with append permission.

And then we call write with the string to append to the file.

For instance, we write:

with open("foo.txt", "a") as myfile:
    myfile.write("appended text")

We call open with the path to the file and 'a' to open the file with append permission.

Then we call write with the string to append to the opened file.

Since we use the with statement to open the file, the file will be closed automatically after the append operation is done.

Conclusion

To append to a file with Python, we can open the file with open with append permission.

And then we call write with the string to append to the file.