Replace words found in string - javascript

Im trying to replace words in string with matched key and index position without removing the other words.
My desired output is: hey HI hey HELLO
What i've tried so far...
var data = {
items: ["item", "HI", "item2"],
moreitems: ["moreitem", "moreitem1", "HELLO"]
}
var str = "hey #items1 hey #moreitems2";
var newStr = '';
var match = str.match(/#(.*?)\d+/g); //get str that starts with # and ends with digits
for (var i = 0; i < match.length; i++) {
var keys = match[i].replace(/#|\d+/g, ''), // remove hash and numbers to match the data keys
pos = match[i].replace(/\D/g, ''); // get the digits in str
newStr += data[keys][pos] + ' ';
}
console.log(newStr)
thanks for your help!

A simple solution would be to use replace() with a replacer function.
I use the regex /#(\D+)(\d+)/g. Matching #, followed by one or more non-digits (placed in capture group 1), followed by one or more digits (placed in capture group 2).
Regexper
All capture groups are passed as arguments of the replacer function. The full match is passed as the first argument, capture group 1 as the second, etc.
Within the replacer function you can then access the value based on the captured attribute name and index.
var data = {
items: ["item", "HI", "item2"],
moreitems: ["moreitem", "moreitem1", "HELLO"]
}
var str = "hey #items1 hey #moreitems2";
const result = str.replace(
/#(\D+)(\d+)/g,
(_match, attr, index) => data[attr][index]
);
console.log(result);

you can use
string.replace to replace the substr in the end of the process
calculate the index in string array by recovered the last character of match string with match[match.length - 1]
recover category of data to use by removing first and last character category = match.slice(0, -1).substring(1);
var data = {
items: ["item", "HI", "item2"],
moreitems: ["moreitem", "moreitem1", "HELLO"]
}
var str = "hey #items1 hey #moreitems2";
var newStr = str;
var match = str.match(/#(.*?)\d+/g);
var index, category;
console.log(match);
match.forEach(match => {
index = match[match.length - 1];
category = match.slice(0, -1).substring(1);
newStr = newStr.replace(match, data[category][index]);
});
console.log(newStr)

const dic = {
xxx: 'hello',
yyy: 'world',
zzz: 'peace'
}
const string = 'hey! #xxx, #yyy! #zzz on you'
const newString = string.replace(/#\w+/g, item => dic[item.substring(1)])
console.log(string)
console.log(newString)

Related

regex (only 1 dot)

I have a regEx where I replace everything whats not a number:
this.value.replace(/[^0-9\.]/g,'');
how can i make sure it will only allow 1 dot
(the second dot will be replaced like the others)
(I know you can use input just number (thats not an option in this project for me))
You can use a simple trick of:
splitting a string by ., and then only joining the first two elements of the array (using .splice(0,2)) with a . and the rest with nothing
using a simple regex pattern to replace all non-digit and non-period characters: /[^\d\.]/gi
Here is an example code:
// Assuming that `yourString` is the input you want to parse
// Step 1: Split and rejoin, keeping only first occurence of `.`
var splitStr = yourString.split('.');
var parsedStr = splitStr[0];
if (splitStr.length) {
parsedStr = splitStr.splice(0, 2).join('.') + splitStr.join('');
}
// Step 2: Remove all non-numeric characters
parsedStr = parsedStr.replace(/[^\d\.]/gi, '');
Proof-of-concept example:
var tests = [
'xx99',
'99xx',
'xx99xx',
'xxxx999.99.9xxx',
'xxxx 999.99.9 xxx',
'xx99xx.xx99xx.x9',
'xx99xx.99x.9x',
'xx99.xx99.9xx'
];
for (var i = 0; i < tests.length; i++) {
var str = tests[i];
// Split and rejoin, keeping only first occurence of `.`
var splitStr = str.split('.');
var parsedStr = splitStr[0];
if (splitStr.length) {
parsedStr = splitStr.splice(0, 2).join('.') + splitStr.join('');
}
// Remove all non-numeric characters
parsedStr = parsedStr.replace(/[^\d\.]/gi, '');
console.log('Original: ' + str + '\nParsed: ' + parsedStr);
}
I resolved it with.
this.value = this.value.replace(/.*?(\d+.\d+).*/g, "$1");

How to split string by first occurrence of a char (:) in JavaScript

I have got following two strings:
1. 'TestKey : TestValue'
2. '"Test : Key" : Test:Value'
Here I want to split both strings by the first occurrence of the char colon (:) and I have to ignore the colon if the string part is enclosed with double quotes.
I have to split the first string as like below:
[TestKey, TestValue]
And need to split the second string like below:
[Test : Key, Test:Value]
Any help would be greatly appreciated in JavaScript with or without Regex.
We need to split first and check the double quotes in every set of data anf if not found add them though join.
var str = '"Test : Key" : Test:Value';
var arr = str.split(':');
var newArr = [];
var ktr = '';
for(let i=0;i<arr.length;i++) {
if(arr[i].indexOf('"') !== -1) {
ktr += arr[i] + ':';
} else {
newArr.push(arr[i]);
}
}
if(ktr !== '') {
ktr = ktr.substring(0,ktr.length-1);
newArr.unshift(ktr);
}
console.log(newArr.join(':'));
Here is a piece of working code using a RegExp testing the strings you provided as examples:
var regex = /\"{0,1}([^"]*)\"{0,1}\s:\s\"{0,1}([^"]*)\"{0,1}/g;
var str1 = 'TestKey : TestValue';
var str2 = '"Test:Key" : Test:Value';
var str3 = '"Test : Key" : Test:Value';
var firstArray = regex.exec(str1);
regex.lastIndex = 0; //reset the regex
var secondArray = regex.exec(str2);
regex.lastIndex = 0; //reset the regex
var thirdArray = regex.exec(str3);
regex.lastIndex = 0; //reset the regex
//remove the first element of each array, which is the whole string
firstArray.shift();
secondArray.shift();
thirdArray.shift();
Hope it helps.
You can test the RegExp here: https://regex101.com/r/PV123v/1

JavaScript: Take first three characters of each word in string and put "_" after each word

What I would like to achieve is take a string:
var string = "Hello there my friend";
And return a formatted string as follows:
"HEL_THE_MY_FRI"
So I am trying to take the first three characters of each word in a string and add an underscore after each. The capitalize is easy :) .toUpperCase()
You could use replace for that:
var string = "Hello there my friend";
var result = string.toUpperCase().replace(/\b(\S{1,3})\S*/g, '$1').replace(/ /g, '_');
console.log(result);
Since you didn't provide any code for what you've tried so far, the steps you'd take are:
split the string on spaces
loop over your array of words
get a substring from each word 3 characters long
uppercase the substring
append it to your new string
add an underscore if it isn't the last word in your array
var phrase = 'this is my string';
var words = phrase.split(' ');
var result = '';
for (var i = 0; i < words.length; i++) {
var word = words[i];
result += word.substring(0, 3).toUpperCase();
if (i < words.length - 1) {
result += '_';
}
}
console.log(result);
"One-line" solution using String.replace(), String.toUpperCase() and String.slice() functions:
var string = "Hello there my friend",
replaced = string.replace(/\b(\w{1,3})(\w+\s?|\s)/g, '$1_').toUpperCase().slice(0,-1);
console.log(replaced);
console.log("Hello there my friend".split(" ").map((a)=>a.substring(0, 3)).join("_").toUpperCase());

How can I replace single digit numbers within a string without affecting 2 digit numbers in that string

I'm working to update this function which currently takes the content and replaces any instance of the target with the substitute.
var content = textArea.value; //should be in string form
var target = targetTextArea.value;
var substitute = substituteTextArea.value;
var expression = new RegExp(target, "g"); //In order to do a global replace(replace more than once) we have to use a regex
content = content.replace(expression, substitute);
textArea.value = content.split(",");
This code somewhat works... given the input "12,34,23,13,22,1,17" and told to replace "1" with "99" the output would be "992,34,23,993,22,99,997" when it should be "12,34,23,13,22,99,17". The replace should only be performed when the substitute is equal to the number, not a substring of the number.
I dont understand the comment about the regex needed to do a global replace, I'm not sure if that's a clue?
It's also worth mentioning that I'm dealing with a string separated by either commas or spaces.
Thanks!
You could do this if regex is not a requirement
var str = "12,34,23,13,22,1,17";
var strArray = str.split(",");
for(var item in strArray)
{
if(strArray[item] === "1")
{
strArray[item] = "99"
}
}
var finalStr = strArray.join()
finalStr will be "12,34,23,13,22,99,17"
Try with this
var string1 = "12,34,23,13,22,1,17";
var pattern = /1[^\d]/g;
// or pattern = new RegExp(target+'[^\\d]', 'g');
var value = substitute+",";//Replace comma with space if u uses space in between
string1 = string1.replace(pattern, value);
console.log(string1);
Try this
target = target.replace(/,1,/g, ',99,');
Documentation
EDIT: When you say: "a string separated by either commas or spaces"
Do you mean either a string with all commas, or a string with all spaces?
Or do you have 1 string with both commas and spaces?
My answer has no regex, nothing fancy ...
But it looks like you haven't got an answer that works yet
<div id="log"></div>
<script>
var myString = "12,34,23,13,22,1,17";
var myString2 = "12 34 23 13 22 1 17";
document.getElementById('log').innerHTML += '<br/>with commas: ' + replaceItem(myString, 1, 99);
document.getElementById('log').innerHTML += '<br/>with spaces: ' + replaceItem(myString2, 1, 99);
function replaceItem(string, needle, replace_by) {
var deliminator = ',';
// split the string into an array of items
var items = string.split(',');
// >> I'm dealing with a string separated by either commas or spaces
// so if split had no effect (no commas found), we try again with spaces
if(! (items.length > 1)) {
deliminator = ' ';
items = string.split(' ');
}
for(var i=0; i<items.length; i++) {
if(items[i] == needle) {
items[i] = replace_by;
}
}
return items.join(deliminator);
}
</script>

regexp split and keep the seperator [duplicate]

I have a string:
var string = "aaaaaa<br />† bbbb<br />‡ cccc"
And I would like to split this string with the delimiter <br /> followed by a special character.
To do that, I am using this:
string.split(/<br \/>&#?[a-zA-Z0-9]+;/g);
I am getting what I need, except that I am losing the delimiter.
Here is the example: http://jsfiddle.net/JwrZ6/1/
How can I keep the delimiter?
I was having similar but slight different problem. Anyway, here are examples of three different scenarios for where to keep the deliminator.
"1、2、3".split("、") == ["1", "2", "3"]
"1、2、3".split(/(、)/g) == ["1", "、", "2", "、", "3"]
"1、2、3".split(/(?=、)/g) == ["1", "、2", "、3"]
"1、2、3".split(/(?!、)/g) == ["1、", "2、", "3"]
"1、2、3".split(/(.*?、)/g) == ["", "1、", "", "2、", "3"]
Warning: The fourth will only work to split single characters. ConnorsFan presents an alternative:
// Split a path, but keep the slashes that follow directories
var str = 'Animation/rawr/javascript.js';
var tokens = str.match(/[^\/]+\/?|\//g);
Use (positive) lookahead so that the regular expression asserts that the special character exists, but does not actually match it:
string.split(/<br \/>(?=&#?[a-zA-Z0-9]+;)/g);
See it in action:
var string = "aaaaaa<br />† bbbb<br />‡ cccc";
console.log(string.split(/<br \/>(?=&#?[a-zA-Z0-9]+;)/g));
If you wrap the delimiter in parantheses it will be part of the returned array.
string.split(/(<br \/>&#?[a-zA-Z0-9]+);/g);
// returns ["aaaaaa", "<br />†", "bbbb", "<br />‡", "cccc"]
Depending on which part you want to keep change which subgroup you match
string.split(/(<br \/>)&#?[a-zA-Z0-9]+;/g);
// returns ["aaaaaa", "<br />", "bbbb", "<br />", "cccc"]
You could improve the expression by ignoring the case of letters
string.split(/()&#?[a-z0-9]+;/gi);
And you can match for predefined groups like this: \d equals [0-9] and \w equals [a-zA-Z0-9_]. This means your expression could look like this.
string.split(/<br \/>(&#?[a-z\d]+;)/gi);
There is a good Regular Expression Reference on JavaScriptKit.
If you group the split pattern, its match will be kept in the output and it is by design:
If separator is a regular expression with capturing parentheses, then
each time separator matches, the results (including any undefined
results) of the capturing parentheses are spliced into the output
array.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split#description
You don't need a lookahead or global flag unless your search pattern uses one.
const str = `How much wood would a woodchuck chuck, if a woodchuck could chuck wood?`
const result = str.split(/(\s+)/);
console.log(result);
// We can verify the result
const isSame = result.join('') === str;
console.log({ isSame });
You can use multiple groups. You can be as creative as you like and what remains outside the groups will be removed:
const str = `How much wood would a woodchuck chuck, if a woodchuck could chuck wood?`
const result = str.split(/(\s+)(\w{1,2})\w+/);
console.log(result, result.join(''));
answered it here also JavaScript Split Regular Expression keep the delimiter
use the (?=pattern) lookahead pattern in the regex
example
var string = '500x500-11*90~1+1';
string = string.replace(/(?=[$-/:-?{-~!"^_`\[\]])/gi, ",");
string = string.split(",");
this will give you the following result.
[ '500x500', '-11', '*90', '~1', '+1' ]
Can also be directly split
string = string.split(/(?=[$-/:-?{-~!"^_`\[\]])/gi);
giving the same result
[ '500x500', '-11', '*90', '~1', '+1' ]
I made a modification to jichi's answer, and put it in a function which also supports multiple letters.
String.prototype.splitAndKeep = function(separator, method='seperate'){
var str = this;
if(method == 'seperate'){
str = str.split(new RegExp(`(${separator})`, 'g'));
}else if(method == 'infront'){
str = str.split(new RegExp(`(?=${separator})`, 'g'));
}else if(method == 'behind'){
str = str.split(new RegExp(`(.*?${separator})`, 'g'));
str = str.filter(function(el){return el !== "";});
}
return str;
};
jichi's answers 3rd method would not work in this function, so I took the 4th method, and removed the empty spaces to get the same result.
edit:
second method which excepts an array to split char1 or char2
String.prototype.splitAndKeep = function(separator, method='seperate'){
var str = this;
function splitAndKeep(str, separator, method='seperate'){
if(method == 'seperate'){
str = str.split(new RegExp(`(${separator})`, 'g'));
}else if(method == 'infront'){
str = str.split(new RegExp(`(?=${separator})`, 'g'));
}else if(method == 'behind'){
str = str.split(new RegExp(`(.*?${separator})`, 'g'));
str = str.filter(function(el){return el !== "";});
}
return str;
}
if(Array.isArray(separator)){
var parts = splitAndKeep(str, separator[0], method);
for(var i = 1; i < separator.length; i++){
var partsTemp = parts;
parts = [];
for(var p = 0; p < partsTemp.length; p++){
parts = parts.concat(splitAndKeep(partsTemp[p], separator[i], method));
}
}
return parts;
}else{
return splitAndKeep(str, separator, method);
}
};
usage:
str = "first1-second2-third3-last";
str.splitAndKeep(["1", "2", "3"]) == ["first", "1", "-second", "2", "-third", "3", "-last"];
str.splitAndKeep("-") == ["first1", "-", "second2", "-", "third3", "-", "last"];
An extension function splits string with substring or RegEx and the delimiter is putted according to second parameter ahead or behind.
String.prototype.splitKeep = function (splitter, ahead) {
var self = this;
var result = [];
if (splitter != '') {
var matches = [];
// Getting mached value and its index
var replaceName = splitter instanceof RegExp ? "replace" : "replaceAll";
var r = self[replaceName](splitter, function (m, i, e) {
matches.push({ value: m, index: i });
return getSubst(m);
});
// Finds split substrings
var lastIndex = 0;
for (var i = 0; i < matches.length; i++) {
var m = matches[i];
var nextIndex = ahead == true ? m.index : m.index + m.value.length;
if (nextIndex != lastIndex) {
var part = self.substring(lastIndex, nextIndex);
result.push(part);
lastIndex = nextIndex;
}
};
if (lastIndex < self.length) {
var part = self.substring(lastIndex, self.length);
result.push(part);
};
// Substitution of matched string
function getSubst(value) {
var substChar = value[0] == '0' ? '1' : '0';
var subst = '';
for (var i = 0; i < value.length; i++) {
subst += substChar;
}
return subst;
};
}
else {
result.add(self);
};
return result;
};
The test:
test('splitKeep', function () {
// String
deepEqual("1231451".splitKeep('1'), ["1", "231", "451"]);
deepEqual("123145".splitKeep('1', true), ["123", "145"]);
deepEqual("1231451".splitKeep('1', true), ["123", "145", "1"]);
deepEqual("hello man how are you!".splitKeep(' '), ["hello ", "man ", "how ", "are ", "you!"]);
deepEqual("hello man how are you!".splitKeep(' ', true), ["hello", " man", " how", " are", " you!"]);
// Regex
deepEqual("mhellommhellommmhello".splitKeep(/m+/g), ["m", "hellomm", "hellommm", "hello"]);
deepEqual("mhellommhellommmhello".splitKeep(/m+/g, true), ["mhello", "mmhello", "mmmhello"]);
});
I've been using this:
String.prototype.splitBy = function (delimiter) {
var
delimiterPATTERN = '(' + delimiter + ')',
delimiterRE = new RegExp(delimiterPATTERN, 'g');
return this.split(delimiterRE).reduce((chunks, item) => {
if (item.match(delimiterRE)){
chunks.push(item)
} else {
chunks[chunks.length - 1] += item
};
return chunks
}, [])
}
Except that you shouldn't mess with String.prototype, so here's a function version:
var splitBy = function (text, delimiter) {
var
delimiterPATTERN = '(' + delimiter + ')',
delimiterRE = new RegExp(delimiterPATTERN, 'g');
return text.split(delimiterRE).reduce(function(chunks, item){
if (item.match(delimiterRE)){
chunks.push(item)
} else {
chunks[chunks.length - 1] += item
};
return chunks
}, [])
}
So you could do:
var haystack = "aaaaaa<br />† bbbb<br />‡ cccc"
var needle = '<br \/>&#?[a-zA-Z0-9]+;';
var result = splitBy(haystack , needle)
console.log( JSON.stringify( result, null, 2) )
And you'll end up with:
[
"<br />† bbbb",
"<br />‡ cccc"
]
Most of the existing answers predate the introduction of lookbehind assertions in JavaScript in 2018. You didn't specify how you wanted the delimiters to be included in the result. One typical use case would be sentences delimited by punctuation ([.?!]), where one would want the delimiters to be included at the ends of the resulting strings. This corresponds to the fourth case in the accepted answer, but as noted there, that solution only works for single characters. Arbitrary strings with the delimiters appended at the end can be formed with a lookbehind assertion:
'It is. Is it? It is!'.split(/(?<=[.?!])/)
/* [ 'It is.', ' Is it?', ' It is!' ] */
I know that this is a bit late but you could also use lookarounds
var string = "aaaaaa<br />† bbbb<br />‡ cccc";
var array = string.split(/(?<=<br \/>)/);
console.log(array);
I've also came up with this solution. No regex needed, very readable.
const str = "hello world what a great day today balbla"
const separatorIndex = str.indexOf("great")
const parsedString = str.slice(separatorIndex)
console.log(parsedString)

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