Tag: regex

How to detect if a string is a number with regex (with JavaScript example)

March 27th, 2023
Reading Time: < 1 minutes
To detect if a string is a number with regex, you can use the following regular expression:
```
^-?\d+(\.\d+)?$
```
Explanation:
- ^ matches the start of the string
- -? matches an optional minus sign (-)
- \d+ matches one or more digits
- (\.\d+)? matches an optional decimal point followed by one or more digits
- $ matches the end of the string
This regular expression will match any string that represents a number, including integers and decimal numbers, with or without a leading minus sign.

Here’s an example of how to use this regular expression to check if a string is a number in JavaScript:
```
function isNumber(str) {
  return /^-?\d+\.?\d*$/.test(str);
}

console.log(isNumber('42')); // true
console.log(isNumber('-3.14')); // true
console.log(isNumber('0')); // true
console.log(isNumber('4.2.1')); // false
console.log(isNumber('hello')); // false
```
The test method returns true if the regular expression matches the given string, and false otherwise.
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How to remove more than two spaces and new lines with regex

March 26th, 2023
Reading Time: < 1 minutes
To remove more than two spaces and new lines using regex, you can use the following pattern:
```
\s{2,}|[\r\n]+
```
This pattern matches any sequence of two or more whitespace characters (\s{2,}) or any sequence of one or more newline characters ([\r\n]+).

To remove these matches from your text using regex, you can use a regex function in your programming language of choice
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How to remove extra spaces and new lines using regex in Notepad++

March 26th, 2023
Reading Time: < 1 minutes
Removing extra spaces and new lines can be a tedious task, especially when dealing with large chunks of text. Thankfully, regular expressions (regex) can make this process much easier and more efficient. In this post, we’ll show you how to remove more than two spaces and new lines with regex in just a few simple steps.

Step 1: Identify the pattern

First, we need to identify the pattern we want to remove. In this case, we want to remove more than two spaces and any new line characters.

Step 2: Create the Regex expression

Next, we’ll create a regex expression to match this pattern. The expression will look like this:
```
`[\r\n\s]{3,}`
```
This expression matches any sequence of three or more space characters, as well as any new line characters.

Step 3: Replace the pattern

Now that we have our regex expression, we can use it to replace the pattern in our text. You can use any text editor that supports regex, such as Notepad++.

Here’s an example of how to do this in Notepad++:

1. Open your text file in Notepad++.
2. Click Ctrl+H to open the “Replace” dialog box.
3. In the “Find what” field, enter the regex expression: `[\r\n\s]{3,}`
4. Leave the “Replace with” field blank.
5. Select “Regular expression” in the “Search Mode” section.
6. Click “Replace All” to remove all instances of the pattern.

That’s it! You have successfully removed more than two spaces and new lines from your text using regex. Using regular expressions can save you a lot of time and effort when working with large chunks of text. We hope you found this tutorial helpful!
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Clean up more than two spaces and new lines with regex

May 11th, 2021

Reading Time: < 1 minutes

Regular expressions are those I don’t use so frequently so I need to wrap them all in a method with a short explanation about what they do.
So I created a simple JavaScript method that removes all newlines and multiple spaces (including tab spaces) by a single space

/**
 * It replace all new lines and multiple spaces (including tab spaces) by a single space
 * @param {string } text
 * @return {string} a new cleaned string
 */
function cleanUpSpaces(text) {
    if (!text) {
        return text;
    }
    // s{2,} matches any white space (length >= 2) character (equal to [rntfv ])
    return text.replace(/s{2,}/g, ' ');
};

Output example

      
// given
`SELECT *
            FROM account        WHERE id =    1234`

// output
SELECT * FROM account WHERE id = 1234

Detect if a string is a number with regex

August 30th, 2020
Reading Time: < 1 minutes
Regular expressions, commonly shortened to regex, are a powerful tool for working with text data in programming. One common task is determining whether a given string is a number. Fortunately, this is a task that can be accomplished with a relatively simple regex pattern.

To implement this regex pattern in code, simply use a regex matching function such as JavaScript’s `test()` method, which returns true or false depending on whether the pattern matches the input string. With this simple regex pattern, you can easily detect whether a given string is a number, making it a valuable addition to your programming toolkit.
```
/**
 * It's not strictly the same than isNumber()
 *
 * @param text
 * @return true if the given text  is s number
 */
function isNumberText (text) {
    if (!text)  return false;
    // the value must be a number, including float and not empty.
    const reg = new RegExp('^-?\d+\.?\d*$');
    return reg.test(text);
};
```
You can test this regex at https://regex101.com/

Examples
```
// it will return true on these cases
12
"12"
32.3
"43.4"

// false for these cases
"22a"
undefined
null
""
"1    2"
```
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Tag: regex

How to detect if a string is a number with regex (with JavaScript example)

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How to remove more than two spaces and new lines with regex

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How to remove extra spaces and new lines using regex in Notepad++

Step 1: Identify the pattern

Step 2: Create the Regex expression

Step 3: Replace the pattern

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Clean up more than two spaces and new lines with regex

Output example

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Detect if a string is a number with regex

Examples

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