Javascript ES5: Find string in array which matches pattern [closed] - javascript

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I need help finding the string that matches specific patterns in an array of strings
For example
var array = ['hello there heretic', "purge the alien", "FOR THE EMPEROR!!" ]
How would I grab "FOR THE EMPEROR!!" if I want to find it by the following 2 separate scenarios:
Grab string in array which starts with "FOR"
Grab string in array that contains "EMPEROR"
They need to be ES5 or below though.

You can use the RegEx for checking the given string matching the requirements. Like this,
var regEx = /(^FOR)|(.*EMPEROR.*)/i;
var array = ['hello there heretic', "purge the alien", "FOR THE EMPEROR!!" ]
array.filter(function(str) { return regEx.test(str) }) // ["FOR THE EMPEROR!!"]
For case-sensitive remove i in regex like: /(^FOR)|(.*EMPEROR.*)/
var regEx = /(^FOR)|(.*EMPEROR.*)/i;
var array = ['hello there heretic', "purge the alien", "FOR THE EMPEROR!!", "For the champion", "And the EMPEROR" ]
const result = array.filter(function(str) { return regEx.test(str) })
console.log({result})

If you need to support lower version of IE, use indexOf instead of
includes.
let array = ['hello there heretic', "purge the alien", "FOR THE EMPEROR!!"];
console.log(array.filter( function(el) {
return el.indexOf("EMPEROR") > -1 && el.split(" ")[0] == "FOR"
}))

Related

Javascript Array - Split string at numbers [closed]

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I have an unknown string containing a set of numbers like so:
var string = "stuff 1.23! (456) 789 stuff";
I would like to split the array, in order to modify the numbers and later rejoin the array. The result I'm looking for should look like this:
var result = ['stuff ', 1.23, '! (', 456, ') ', 789, ' stuff'];
Is there a better solution than to loop through each character individually? Thanks!
use a character class to split the values:
/(-?[\d.]+)/
-? May start with a negative such as -123
[\d.]+ Has one or more numbers and decimals
var string = "stuff 1.23! (456) 789 stuff -234".split(/(-?[\d.]+)/);
console.log(string)
The ideal solution really depends on what exactly you are doing with the data. One simple solution is a regular expression with replace.
var string = "stuff 1.23! (456) 789 stuff";
var updated = string.replace(/\d+(\.\d+)?/g, function (m) {
console.log(m);
return "xxx";
})
console.log(updated)
A regular expression is an expression you can use to search within your string, in you case, for digits. Create a regular expression which searches for sequences of digits, and you'll be able to use the split method on your string to create an array of strings like you specified.

Strip specific characters and replaced with word [closed]

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If I have this string:
This string should #[1234] by another word
I want to replace to remove # [ ] and replace 1234 with 'test' word for example so the result is:
This string should test by another word
Is there any way to do this with js?
You can use regular expression to repalce your #[XXX] by test with the following code :
var string = "This string should #[1234] by another word";
console.log(string.replace(/#\[[0-9]+\]/gi, "test"));
I suggest to define a mapping from ids to replacements first.
Then you use string.replace(regex, callback) with a regex that matches #[1234] or any other id within the brackets and captures the id within a capture group.
Finally, you provide a callback which receives the value of the capture group as the second parameter and performs the replacement according to your mapping:
const input = 'This string should #[1234] by another word';
const replacements = {'1234': 'test'};
const output = input.replace(/#\[(\d+)\]/g, (match, id) => replacements[id]);
console.log(output);
I'm guessing you have multiple texts to replace? If so, you can use the String.replace function with a callback, which provides the replacement value. Something like this:
var repls = {
"1234": "test"
};
var text = "This string should #[1234] by another word";
var result = text.replace(/#\[([0-9]+)\]/g, function(entireMatch, key) {
return repls[key];
});
console.log(result);
Here's some code that doesn't use regular expressions, just split() and join(), and with strings as delimiters.
str='This string should #[1234] by another word';
console.log(str.split('#[1234]').join('test'));

split a string with comma and colon [closed]

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I have a string like as shown below:
var String = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string without comma,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string,with comma,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string without comma,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string , with comma,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:String,with comma"
Where xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx represents an alphanumeric generated Id and after the colon is a string related to that Id.The string can be a string with comma or without comma.What I wanted was that I wanted to split the string such that I get an array with ID:its corresponding string , just like shown below.
["xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string without comma","xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string,with comma","xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string","xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string without comma",
"xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:some string , with comma","xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:String,with comma"]
HOW I ACCOMPLISHED THIS
I used the javascript split function where i split the string by comma followed by 36 characters (for ID) and colon.
String.split(/,(?=.{36}:)/);
PS: I apologize as previously I was not able to ask the question in the correct manner.Hope this time people understand it.
You could use String#split by comma and a look ahead for numbers and colon.
var x = "123456:a,b,c,435213:r,567876:e,363464:t,y,u";
array = x.split(/,(?=\d+:)/);
console.log(array);
For alphanumeric values
var x = "1A3456:a,b,c,43Y213:r,567W76:e,363x64:t,y,u";
array = x.split(/,(?=[a-z0-9]+:)/i);
console.log(array);
You can use the method .split(). I used the "$" as a split sign instead of "," because i thought you would like to keep them.
var values = "123456:a,b,c$435213:r$567876:e$363464:t,y,u".split("$");
var x = values[0];
console.log(values)

Get regex rules for a capture group [closed]

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I am looking for a method to get the regex rules, for a capture group.
So if I had: /(\w) (\d)/ I would want $1 = /\w/ and $2 = /\d/.
Is there a method for this?
Provided that the regex is valid and no nested groups are used, then you can try this out.
var arr = (regex + "").match(/\(.*?\)/g).map(function(rule){
return rule.replace(/[()]/g, "");
});
Now, arr[0] will have rule of group1, arr[1] will be group2 and so on.
Although I don't know of any direct way to do this on a regex rule given by /(rule1)(rule2)/ you could build the regex rule using strings and specify your grouping in different strings.
var group1 = '([A-Za-z]+)',
group2 = '(\\d+)',
r = new RegExp(group1+group2);
r.test('hello1234');
To get the groups from a regex string you could run a regex on that regex string to extract the groups. If your regex string is "(\w+)(\d+)" then you'd have a regex to extract the groups as /(\([^\)\))+/

Get all values between '[ ]' on a string with JavaScript [closed]

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How are you guys doing?
I'd like to ask today if you could help me with a tricky question that I was unable to solve on my own.
I [have] strings that [are] like this.
I was looking for a way to get "have" and "are" and form an array with them using JavaScript. Please notice that this is an example. Sometimes I have several substrings between braces, sometimes I don't have braces at all on my strings.
My attempts focused mostly on using .split method and regex to accomplish it, but the closest I got to success was being able to extract the first value only.
Would any of you be so kind and lend me an aid on that?
I tried using the following.
.split(/[[]]/);
You can use the exec() method in a loop, pushing the match result of the captured group to the results array. If the string has no square brackets, you will get an empty matches array [] returned.
var str = 'I [have] strings that [are] like this.'
var re = /\[([^\]]*)]/g,
matches = [];
while (m = re.exec(str)) {
matches.push(m[1]);
}
console.log(matches) //=> [ 'have', 'are' ]
Note: This will only work correctly if the brackets are balanced, will not perform on nested brackets.
var str = "I [have] strings that [are] like this";
var res = str.split(" ");
The result of res will be an array with the values:
I
[have]
strings
that
[are]
like
this
If you want to get only values between braces, you can use the following regex expression:
var str = "I [have] strings that [are] like this";
var result = [];
var pattern = /\[(.*?)\]/g;
var match;
while ((result = pattern.exec(str)) != null)
{
result.push(match[1]);
}
This is JSFiddle example for you.
Simple as this:
'I [have] strings that [are] like this.'.match(/\[([^\]]*)]/g)

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