We Keep Coding

Javascript: split a string according to two criteria?

I am trying to count the number of sentences in a paragraph. In the paragraph, all sentences end with either ''.'' or ''!''.
My idea is to first split the paragraph into strings whenever there's a ''.'' or ''!'' and then count the number of splitted strings.
I have tried
.split('.' || '!')
but that does not work. It only splits strings whenever there is a ''.''
May I know how to deal with this?

Just use a Regexp, it's pretty simple ;)
const example = 'Hello! You should probably use a regexp. Nice isn\'t it?';
console.log(example.split(/[.!]/));

You will need to use a regex for this.
The following should work:
.split(/\.|!/)

You can use regex /\.|!/ in split() as str.split(/\.|!/) :
var str = 'some.string';
console.log(str.split(/\.|!/));
str = 'some.string!name';
console.log(str.split(/\.|!/));

const sampleString = 'I am handsome. Are you sure?! Just kidding. Thank you.';
const result = sampleString.split(/\.|!/)
console.log(result);
// to remove elements that has no value you can do
const noEmptyElements = result.filter(str => str);
console.log(noEmptyElements);

Try below code it will give you an exact count of sentences in the paragraph.
function count(string,char) {
var re = new RegExp(char,"gi");
return string.match(re).length;
}
function myFunction() {
var str = 'but that! does! not work. It only splits strings whenever there is a. ';
console.log(count(str,'[.?!]'));
}

Using RegExp to substring a string at the position of a special character

Suppose I have a sting like this: ABC5DEF/G or it might be ABC5DEF-15 or even just ABC5DEF, it could be shorter AB7F, or AB7FG/H.
I need to create a javascript variable that contains the substring only up to the '/' or the '-'. I would really like to use an array of values to break at. I thought maybe to try something like this.
...
var srcMark = array( '/', '-' );
var whereAt = new RegExp(srcMark.join('|')).test.str;
alert("whereAt= "+whereAt);
...
But this returns an error: ReferenceError: Can't find variable: array
I suspect I'm defining my array incorrectly but trying a number of other things I've been no more successful.
What am I doing wrong?

Arrays aren't defined like that in JavaScript, the easiest way to define it would be with:
var srcMark = ['/','-'];
Additionally, test is a function so it must be called as such:
whereAt = new RegExp(srcMark.join('|')).test(str);
Note that test won't actually tell you where, as your variable suggests, it will return true or false. If you want to find where the character is, use String.prototype.search:
str.search(new RegExp(srcMark.join('|'));
Hope that helps.

You need to use the split method:
var srcMark = Array.join(['-','/'],'|'); // "-|/" or
var regEx = new RegExp(srcMark,'g'); // /-|\//g
var substring = "222-22".split(regEx)[0] // "222"
"ABC5DEF/G".split(regEx)[0] // "ABC5DEF"

From whatever i could understand from your question, using this RegExp /[/-]/ in split() function will work.
EDIT:
For splitting the string at all special characters you can use new RegExp(/[^a-zA-Z0-9]/) in split() function.
var arr = "ABC5DEF/G";
var ans = arr.split(/[/-]/);
console.log(ans[0]);
arr = "ABC5DEF-15";
ans = arr.split(/[/-]/);
console.log(ans[0]);
// For all special characters
arr = "AB7FG/H";
ans = arr.split(new RegExp(/[^a-zA-Z0-9]/));
console.log(ans[0]);

You can use regex with String.split.
It will look something like that:
var result = ['ABC5DEF/G',
'ABC5DEF-15',
'ABC5DEF',
'AB7F',
'AB7FG/H'
].map((item) => item.split(/\W+/));
console.log(result);
That will create an Array with all the parts of the string, so each item[0] will contain the text till the / or - or nothing.

If you want the position of the special character (non-alpha-numeric) you can use a Regular Expression that matches any character that is not a word character from the basic Latin alphabet. Equivalent to [^A-Za-z0-9_], that is: \W
var pattern = /\W/;
var text = 'ABC5DEF/G';
var match = pattern.exec(text);
var position = match.index;
console.log('character: ', match[0]);
console.log('position: ', position);

get all but last occurrences of a pattern in javascript

Given the following patterns:
"profile[foreclosure_defenses_attributes][0][some_text]"
"something[something_else_attributes][0][hello_attributes][0][other_stuff]"
I am able to extract the last part using non-capturing groups:
var regex = /(?:\w+(\[\w+\]\[\d+\])+)(\[\w+\])/;
str = "profile[foreclosure_defenses_attributes][0][properties_attributes][0][other_stuff]";
match = regex.exec(str);
["profile[foreclosure_defenses_attributes][0][properties_attributes][0][other_stuff]", "[properties_attributes][0]", "[other_stuff]"]
However, I want to be able to get everything but the last part. In other words, everything but [some_text] or [other_stuff].
I cannot figure out how to do this with noncapturing groups. How else can I achieve this?

Something like?
shorter, and matches from the back if you can have more of the [] items.
var regex = /(.*)(?:\[\w+\])$/;
var a = "something[something_else_attributes][0][hello_attributes][0][other_stuff11][other_stuff22][other_stuff33][other_stuff44]".match(regex)[1];
a;
or using replace, though less performant.
var regex = /(.*)(?:\[\w+\])$/;
var a = "something[something_else_attributes][0][hello_attributes][0][other_stuff11][other_stuff22][other_stuff33][other_stuff44]".replace(regex, function(_,$1){ return $1});
a;

If those really are your strings:
var regex = /(.*)\[/;

Change occurrences of sum(something) to something_sum

Admittedly I'm terrible with RegEx and pattern replacements, so I'm wondering if anyone can help me out with this one as I've been trying now for a few hours and in the process of pulling my hair out.
Examples:
sum(Sales) needs to be converted to Sales_sum
max(Sales) needs to be converted to Sales_max
min(Revenue) needs to be converted to Revenue_min
The only available prefixed words will be sum, min, max, avg, xcount - not sure if this makes a difference in the solution.
Hopefully that's enough information to kind of show what I'm trying to do. Is this possible via RegEx?
Thanks in advance.

There are a few possible ways, for example :
var str = "min(Revenue)";
var arr = str.match(/([^(]+)\(([^)]+)/);
var result = arr[2]+'_'+arr[1];
result is then "Revenue_min".
Here's a more complex example following your comment, handling many matches and lowercasing the verb :
var str = "SUM(Sales) + MIN(Revenue)";
var result = str.replace(/\b([^()]+)\(([^()]+)\)/g, function(_,a,b){
return b+'_'+a.toLowerCase()
});
Result : "Sales_sum + Revenue_min"

Try with:
var input = 'sum(Sales)',
matches = input.match(/^([^(]*)\(([^)]*)/),
output = matches[2] + '_' + matches[1];
console.log(output); // Sales_sum
Also:
var input = 'sum(Sales)',
output = input.replace(/^([^(]*)\(([^)]*)\)/, '$2_$1');

You can use replace with tokens:
'sum(Sales)'.replace(/(\w+)\((\w+)\)/, '$2_$1')

Using a whitelist for your list of prefixed words:
output = input.replace(/\b(sum|min|max|avg|xcount)\((.*?)\)/gi,function(_,a,b) {
return b.toLowerCase()+"_"+a;
});
Added \b, a word boundary. This prevents something like "haxcount(xorz)" from becoming "haxorz_xcount"

how to get numbers from a string in javascript?

I have
"id": 1468306
inside of a string, how can I use regular expression to get the number 1468306 for it?

You can use this regex:
/: (\d+)/
as in:
s = '"id": 1468306';
r = /: (\d+)/;
console.log(r.exec(s)[1]);
Output:
1468306

you can use parseInt() method in javascript as follows:
var str = parseInt(id);

Following code may help you:
var input = '"id": 1468306';
var matches = input.match(/"id": (\d+)/);
var id = matches[1];
The id get the required number.

JSON.parse("{" + yourString + "}").id
Will be your number if you have that in a String.

Fiddle: http://jsfiddle.net/SfeMh/
var regEx = /\d+/g;
var str = '"id": 1468306';
var numbers = str.match(regEx);
alert(numbers); // returns 1468306
It looks like you're trying to parse a JSON String. Try this way as already mentioned:
var parsedObj = JSON.parse(myJSONString);
alert(parsedObj.id); // returns 1468306

This will match in this cases
id : 156454;
id :156454;
id:156454;
/id\s?[:]\s?[0-9]+/g.match(stringhere)

Alright, my JSON answer still stands, use it if that's your full string you're giving us in the question. But if you really want a regex, here's one that will search for "id" and then find the number after.
parseInt(yourString.match(/("id"\s?:\s?)(\d+)/)[2])
Fiddle: http://jsfiddle.net/tS9M4/