Match words in a string and make them lowercase

Question

I have this example string:

var string = 'This is a süPer NICE Sentence, am I right?';

The result has to be:

this, is, süper, nice, sentence

Requirements:

5 words max,
words that contain at least 2 characters
comma separated
takes care of special characters such as ü this is not currently happening
all in lowercase this is not currently happening

This is my current script: (you can test it in jsfiddle)

var string = 'This is a süPer NICE Sentence, am I right?';
var words;
words = string.replace(/[^a-zA-Z\s]/g,function(str){return '';});
words = words.match(/\w{2,}/g);

if(words != null) {
    //5 words maximum
    words = words.slice(0,5);
    if(words.length) {
        console.log(words.join(', ')); //should print: this, is, süper, nice, sentence
    }
}

What would be the best way to convert the matched words into lowercase before the join?

score 1 · Accepted Answer · edited May 23 '17 at 11:58

1

The answer is definitely toLowerCase(), but I think the best place to run it is right at the end rather than the beginning (fewer items to operate on):

if(words != null) {
    //5 words maximum
    words = words.slice(0,5);
    if(words.length) {
        console.log(words.join(', ').toLowerCase()); //here
    }
}

toLowerCase() is, as far as I know, unicode-friendly. Your regex is stripping anything not a-z,A-Z.

Asker found this link helpful for resolving regex issue: Regular expression to match non-English characters?

edited May 23 '17 at 11:58

Community

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answered Jul 14 '15 at 17:35

Gray

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toLowerCase() is deleting special characters (ü)... I updated the example to consider that as well. – Andres SK Jul 14 '15 at 17:39
@andufo `words = string.replace(/[^a-zA-Z\s]/g,function(str){return '';});` is what is deleting those characters. – Gray Jul 14 '15 at 17:40
how could the regex consider special characters as well? – Andres SK Jul 14 '15 at 17:43
@andufo I'm not great with regex, maybe this: http://stackoverflow.com/questions/150033/regular-expression-to-match-non-english-characters Might have to exclude numbers too... not too sure. – Gray Jul 14 '15 at 17:45
Awesome. Glad I could help. – Gray Jul 14 '15 at 17:52
Just fyi this is not correct becuase `string.replace(/[^a-zA-Z\s]/g,function(str){return '';});` will leave `This is a sPer NICE Sentence am I right` **eating away** `ü` in `süPer` – anubhava Jul 14 '15 at 18:09
@anubhava you're right, but I used the solution available in the link for the correct conversion which ended up being the perfect regex. – Andres SK Jul 14 '15 at 22:41
Can you update the question with your reworked solution to benefit others. – anubhava Jul 15 '15 at 06:21

asmockler · Answer 2 · 2015-07-14T17:48:42.580

1

Just use .toLowerCase() .

var string = 'This is a süPer NICE Sentence, am I right?';
string = string.toLowerCase();
var words = string.split(' ');

//5 words maximum
words = words.slice(0,5);

console.log(words.join(', ')); //should print: this, is, super, nice, sentence

The special characters were being filtered out by the regex - if you know the words are separated by a whitespace, just use string.split(' ');

edited Jul 14 '15 at 17:48

answered Jul 14 '15 at 17:37

asmockler

187
7

sorry, I added a special consideration. the toLowerCase() is deleting special characters (ü)... I updated the example. – Andres SK Jul 14 '15 at 17:38
Just noticed that `replace(/[^a-zA-Z\s]/g,function(str){return '';})` is removing the caracter. How could I consider the ü character in that regex? – Andres SK Jul 14 '15 at 17:43

score 0 · Answer 3 · answered Jul 14 '15 at 17:33

0

Just lowercase the string from the start

string.toLowerCase().replace(...

answered Jul 14 '15 at 17:33

epascarello

204,599
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The problem with the toLowerCase() method is that it deletes special characters such as: Ü – Andres SK Jul 14 '15 at 17:35
@andufo "abvcÜ".toLowerCase() === "abvcü". – Gray Jul 14 '15 at 17:37
strange... I just tested the example at https://jsfiddle.net/ox8ux408/1/ and the ü gets removed. – Andres SK Jul 14 '15 at 17:40
1

That would be your reg exp removing the ü not the toLowerCase() – epascarello Jul 14 '15 at 17:42

score 0 · Answer 4 · answered Jul 14 '15 at 17:35

0

Alternatively, you could map the word array to a lowercase string using Array#map.

console.log(words.map(function(word) { return word.toLowerCase(); }).join(', '));

answered Jul 14 '15 at 17:35

Joey Robert

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score 0 · Answer 5 · answered Jul 14 '15 at 17:37

0

You can use toLowerCase method of a string to first convert the string into lower case and then do all the manipulations you need to do on the string.

eg: var string = 'This is a suPer NICE Sentence, am I right?'.toLowerCase();

answered Jul 14 '15 at 17:37

sahil gupta

2,339
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Match words in a string and make them lowercase

5 Answers5