I have a string. It's just like;
var str = "This is an example sentence, thanks.";
I want to change every fifth element of this string.
for(var i=5; i<=str.length; i=i+5)
{
str[i]='X'; // it doesn't work, I need something like that
}
So I want str to be "ThisXis aX exaXple XenteXce, XhankX."
Is there any way to do that?
Use RegEx
str = str.replace(/(....)./g, "$1X")
jsfiddle
var str = "This is an example sentence, thanks.";
var newString = "";
for(var i=0; i<str.length; i++)
{
if ((i % 5) == 4) {
newString += "X";
} else {
newString += str.charAt(i);
}
}
Here is a running example. http://jsfiddle.net/WufuK/1
You could use a map, although the regex solution looks better.
str = str.split('').map(function(chr, index){
return (index % 5 === 4)? 'X' : chr;
}).join('');
You can use string.substring()
var a = "This is an example sentence, thanks.";
var result ="";
for(var i=0;i <a.length-1; i+=5){
result +=a.substr(i, 4)+'X';
}
alert(result)
jsFiddle: http://jsfiddle.net/mVb4u/5
This approach uses Array.reduce, which is native to JavaScript 1.8, but can be backported.
Array.prototype.reduce.call("This is an example sentence, thanks.", function(p,c,i,a) { return p + ( i % 5 == 4 ? "X" : c); });
Update: Updated to reflect am not i am's comments below.
Related
I'm working on alternating the case of a string (for example asdfghjkl to AsDfGhJkL).
I tried to do this. I found some code that is supposed to do it, but it doesn't seem to be working.
var str="";
var txt=document.getElementById('input').value;
for (var i=0; i<txt.length; i+2){
str = str.concat(String.fromCharCode(txt.charCodeAt(i).toUpperCase()));
}
Here's a quick function to do it. It makes the entire string lowercase and then iterates through the string with a step of 2 to make every other character uppercase.
var alternateCase = function (s) {
var chars = s.toLowerCase().split("");
for (var i = 0; i < chars.length; i += 2) {
chars[i] = chars[i].toUpperCase();
}
return chars.join("");
};
var txt = "hello world";
console.log(alternateCase(txt));
HeLlO WoRlD
The reason it converts the string to an array is to make the individual characters easier to manipulate (i.e. no need for String.prototype.concat()).
Here an ES6 approach:
function swapCase(text) {
return text.split('').map((c,i) =>
i % 2 == 0 ? c.toLowerCase() : c.toUpperCase()
).join('');
}
console.log(swapCase("test"))
You should iterate the string and alternate between upper-casing the character and lower-casing it:
for (var i=0; i<txt.length; i++) {
var ch = String.fromCharCode(txt.charCodeAt(i);
if (i % 2 == 1) {
ch = ch.toUpperCase();
} else {
ch = ch.toLowerCase();
}
str = str.concat(ch);
}
I am trying to replace all dots for comma and commas for dots and was wondering what is the best practice for doing this. If I do it sequentially, then the steps will overwrite each other.
For example:
1,234.56 (after replacing commas) --> 1.234.56 (after replacing dots) --> 1,234,56
Which is obviously not what I want.
One option I guess is splitting on the characters and joining afterwards using the opposite character. Is there an easier/better way to do this?
You could use a callback
"1,234.56".replace(/[.,]/g, function(x) {
return x == ',' ? '.' : ',';
});
FIDDLE
If you're going to replace more than two characters, you could create a convenience function using a map to do the replacements
function swap(str, swaps) {
var reg = new RegExp('['+Object.keys(swaps).join('')+']','g');
return str.replace(reg, function(x) { return swaps[x] });
}
var map = {
'.':',',
',':'.'
}
var result = swap("1,234.56", map); // 1.234,56
FIDDLE
You could do the following:
var str = '1,234.56';
var map = {',':'.','.':','};
str = str.replace(/[,.]/g, function(k) {
return map[k];
});
Working Demo
Do it in stages using placeholder text:
var foo = '1,234.56';
foo = foo
.replace(',', '~comma~')
.replace('.', '~dot~')
.replace('~comma~', '.')
.replace('~dot~', ',')
You could use a for loop. Something like:
var txt = document.getElementById("txt");
var newStr = "";
for (var i = 0; i < txt.innerHTML.length; i++){
var char = txt.innerHTML.charAt(i);
if (char == "."){
char = ",";
}else if (char == ","){
char = ".";
}
newStr += char;
}
txt.innerHTML = newStr;
Here's a fiddle:
http://jsfiddle.net/AyLQt/1/
Have to say though, #adenoeo's answer is way more slick :D
In javascript you can use
var value = '1.000.000,55';
var splitValue = value.split('.');
for (var i = 0; i < splitValue.length; i++) {
var valPart = splitValue[i];
var newValPart = valPart.replace(',', '.');
splitValue[i] = newValPart;
}
var newValue = splitValue.join(',');
console.log(newValue);
I want to remove all empty values from an url:
var s="value1=a&value2=&value3=b&value4=c&value5=";
s = s.replace(...???...);
alert(s);
Expected output:
value1=a&value3=b&value4=c
I only need the query part of the URL to be taken into account.
Something like this:
s = s.replace(/[^=&]+=(&|$)/g,"").replace(/&$/,"");
That is, remove groups of one or more non-equals/non-ampersand characters that are followed by an equals sign and ampersand or end of string. Then remove any leftover trailing ampersand.
Demo: http://jsfiddle.net/pKHzr/
s = s.replace(/[^?=&]+=(&|$)/g,"").replace(/&$/,"");
Added a '?' to nnnnnn's answer to fix the issue where the first parameter is empty in a full URL.
This should do the trick:
var s="value1=a&value2=&value3=b&value4=c&value5=";
var tmp = s.split('&')
var newS = '';
for(var i in a) {
var t = a[i];
if(t[t.length - 1] !== '=') {
newS += t + '&';
}
}
if(newS[newS.length - 1] === '&') {
newS = newS.substr(0, newS.length - 1);
}
console.log(newS);
I don't find any solution to do that with one Regex expression.
But you could loop through your string and construct a new result string : http://jsfiddle.net/UQTY2/3/
var s="value1=a&value2=&value3=b&value4=c&value5=";
var tmpArray = s.split('&');
var final = '';
for(var i=0 ; i<tmpArray.length ; i++)
if(tmpArray[i].split('=')[1] != '')
final += tmpArray[i] + '&';
final = final.substr(0,final.length-1)
alert(final)
Where do you take all the values?
I suggest using an array:
function getValues(str){
var values = [];
var s = str.split('&');
for(var val in s){//source is a
var split = val.split('=');
if(split [1] != '' && split [1] != null){
values.push(val);
}
}
return values.join('&');
}
I would like to replace every other comma in a string with a semicolon.
For example:
1,2,3,4,5,6,7,8,9,10
would become
1;2,3;4,5;6,7;8,9;10
What would be the regexp to do this? An explanation would be great.
Thank you :)
var myNums = "1,2,3,4,5,6,7,8,9,10";
myNums.replace(/(.*?),(.*?,)?/g,"$1;$2");
That'll do it.
var str = '1,2,3,4,5,6,7,8,9,10';
str.replace(/,(.*?,)?/g, ';$1');
// Now str === "1;2,3;4,5;6,7;8,9;10"
You would do something like this:
myString.replace(/,/g, ';');
You could use this regex pattern
([^,]*),([^,]*),?
And replace with $1;$2,. The question mark on the end is to account for the lack of a comma signaling the end of the last pair.
For example...
var theString = "1,2,3,4,5,6,7,8,9,10";
theString = theString.replace(/([^,]*),([^,]*),?/ig, "$1;$2,"); //returns "1;2,3;4,5;6,7;8,9;10,"
theString = theString.substring(0, theString.length - 1); //returns "1;2,3;4,5;6,7;8,9;10"
A non-regex answer:
function alternateDelims(array, delim_one, delim_two) {
var delim = delim_one,
len = array.length,
result = [];
for(var i = 0; i < len; i += 1) {
result.push(array[i]);
if(i < len-1) { result.push(delim); }
delim = (delim === delim_one) ? delim_two : delim_one;
}
return result.join('');
}
nums = "1,2,3,4,5,6,7,8,9,10"
alternateDelims(nums.split(','), ';', ',');
I'm wondering if there's a way to count the words inside a div for example. Say we have a div like so:
<div id="content">
hello how are you?
</div>
Then have the JS function return an integer of 4.
Is this possible? I have done this with form elements but can't seem to do it for non-form ones.
Any ideas?
g
If you know that the DIV is only going to have text in it, you can KISS:
var count = document.getElementById('content').innerHTML.split(' ').length;
If the div can have HTML tags in it, you're going to have to traverse its children looking for text nodes:
function get_text(el) {
ret = "";
var length = el.childNodes.length;
for(var i = 0; i < length; i++) {
var node = el.childNodes[i];
if(node.nodeType != 8) {
ret += node.nodeType != 1 ? node.nodeValue : get_text(node);
}
}
return ret;
}
var words = get_text(document.getElementById('content'));
var count = words.split(' ').length;
This is the same logic that the jQuery library uses to achieve the effect of its text() function. jQuery is a pretty awesome library that in this case is not necessary. However, if you find yourself doing a lot of DOM manipulation or AJAX then you might want to check it out.
EDIT:
As noted by Gumbo in the comments, the way we are splitting the strings above would count two consecutive spaces as a word. If you expect that sort of thing (and even if you don't) it's probably best to avoid it by splitting on a regular expression instead of on a simple space character. Keeping that in mind, instead of doing the above split, you should do something like this:
var count = words.split(/\s+/).length;
The only difference being on what we're passing to the split function.
Paolo Bergantino's second solution is incorrect for empty strings or strings that begin or end with whitespaces. Here's the fix:
var count = !s ? 0 : (s.split(/^\s+$/).length === 2 ? 0 : 2 +
s.split(/\s+/).length - s.split(/^\s+/).length - s.split(/\s+$/).length);
Explanation: If the string is empty, there are zero words; If the string has only whitespaces, there are zero words; Else, count the number of whitespace groups without the ones from the beginning and the end of the string.
string_var.match(/[^\s]+/g).length
seems like it's a better method than
string_var.split(/\s+/).length
At least it won't count "word " as 2 words -- ['word'] rather than ['word', '']. And it doesn't really require any funny add-on logic.
Or just use Countable.js to do the hard job ;)
document.deepText= function(hoo){
var A= [];
if(hoo){
hoo= hoo.firstChild;
while(hoo!= null){
if(hoo.nodeType== 3){
A[A.length]= hoo.data;
}
else A= A.concat(arguments.callee(hoo));
hoo= hoo.nextSibling;
}
}
return A;
}
I'd be fairly strict about what a word is-
function countwords(hoo){
var text= document.deepText(hoo).join(' ');
return text.match(/[A-Za-z\'\-]+/g).length;
}
alert(countwords(document.body))
Or you can do this:
function CountWords (this_field, show_word_count, show_char_count) {
if (show_word_count == null) {
show_word_count = true;
}
if (show_char_count == null) {
show_char_count = false;
}
var char_count = this_field.value.length;
var fullStr = this_field.value + " ";
var initial_whitespace_rExp = /^[^A-Za-z0-9]+/gi;
var left_trimmedStr = fullStr.replace(initial_whitespace_rExp, "");
var non_alphanumerics_rExp = rExp = /[^A-Za-z0-9]+/gi;
var cleanedStr = left_trimmedStr.replace(non_alphanumerics_rExp, " ");
var splitString = cleanedStr.split(" ");
var word_count = splitString.length -1;
if (fullStr.length <2) {
word_count = 0;
}
if (word_count == 1) {
wordOrWords = " word";
} else {
wordOrWords = " words";
}
if (char_count == 1) {
charOrChars = " character";
} else {
charOrChars = " characters";
}
if (show_word_count & show_char_count) {
alert ("Word Count:\n" + " " + word_count + wordOrWords + "\n" + " " + char_count + charOrChars);
} else {
if (show_word_count) {
alert ("Word Count: " + word_count + wordOrWords);
} else {
if (show_char_count) {
alert ("Character Count: " + char_count + charOrChars);
}
}
}
return word_count;
}
The get_text function in Paolo Bergantino's answer didn't work properly for me when two child nodes have no space between them. eg <h1>heading</h1><p>paragraph</p> would be returned as headingparagraph (notice lack of space between the words). So prepending a space to the nodeValue fixes this. But it introduces a space at the front of the text but I found a word count function that trims it off (plus it uses several regexps to ensure it counts words only). Word count and edited get_text functions below:
function get_text(el) {
ret = "";
var length = el.childNodes.length;
for(var i = 0; i < length; i++) {
var node = el.childNodes[i];
if(node.nodeType != 8) {
ret += node.nodeType != 1 ? ' '+node.nodeValue : get_text(node);
}
}
return ret;
}
function wordCount(fullStr) {
if (fullStr.length == 0) {
return 0;
} else {
fullStr = fullStr.replace(/\r+/g, " ");
fullStr = fullStr.replace(/\n+/g, " ");
fullStr = fullStr.replace(/[^A-Za-z0-9 ]+/gi, "");
fullStr = fullStr.replace(/^\s+/, "");
fullStr = fullStr.replace(/\s+$/, "");
fullStr = fullStr.replace(/\s+/gi, " ");
var splitString = fullStr.split(" ");
return splitString.length;
}
}
EDIT
kennebec's word counter is really good. But the one I've found includes a number as a word which is what I needed. Still, that's easy to add to kennebec's. But kennebec's text retrieval function will have the same problem.
This should account for preceding & trailing whitespaces
const wordCount = document.querySelector('#content').innerText.trim().split(/\s+/).length;
string_var.match(/[^\s]+/g).length - 1;