I have to split the values using JavaScript and want to find the last occuring slash / from a string and replace the contents after the last slash / For example:
var word = "www.abc/def/ghf/ijk/**default.aspx**";
should become
var word ="www.abc/def/ghf/ijk/**replacement**";
The number of slashes may vary each time.
Try using regexp:
"www.abc/def/ghf/ijk/default.aspx".replace(/\/[^\/]+$/, "/replacement");
An alternative without regular expression (I just remembered lastIndexOf() method)
var word = "www.abc/def/ghf/ijk/default.aspx";
word = word.substring(0, word.lastIndexOf("/")) + "/replacement";
You can array split on '/', then pop the last element off the array, and rejoin.
word = word.split('/');
word.pop();
word = word.join('/') + replacement;
How about the KISS principle?
var word = "www.abc/def/ghf/ijk/default.aspx";
word = word.substring(0, word.lastIndexOf("/")) + "/replacement";
What about using a combination of the join() and split() functions?
var word = "www.abc/def/ghf/ijk/default.aspx";
// split the word using a `/` as a delimiter
wordParts = word.split('/');
// replace the last element of the array
wordParts[wordParts.length-1] = 'replacement';
// join the array back to a string.
var finalWord = wordParts.join('/');
The number of slashes doesn't matter here because all that is done is to split the string at every instance of the delimiter (in this case a slash).
Here is a working demo
Use regexp or arrays, something like:
[].splice.call(word = word.split('/'), -1, 1, 'replacement');
word = word.join('/');
Related
How can I find and replace for example every third occurrence of 'x' character in string with regular expression?
There is similar question but it addresses every fourth character but I need every "nth" occurrence of specific character in string.
I'm using JavaScript replace() method, this below example will change every x character to y:
replace(/\x/g, 'y')
But how can I write regex for question above?
Some random text for example, and expected result:
I amx nexver axt hoxme on Sxundxaxs.
to:
I amx nexver ayt hoxme on Sxundyaxs.
I can use JS for loop with split() and join() but solution with replace() method seams more elegant.
You can use:
str = str.replace(/((?:[^x]*x){2}[^x]*)x/g, '$1y');
So if you are searching for every 3rd occurrence then use n-1 between {} in above regex.
To build it dynamically use:
let str = 'I amx nexver axt hoxme on Sxundxaxs';
let n = 3;
let ch = 'x';
let regex = new RegExp("((?:[^" +ch+ "]*" +ch+ "){" + (n-1) + "}[^" +ch+ "]*)" +ch, "g");
str = str.replace(regex, '$1y');
console.log(str);
//=> I amx nexver ayt hoxme on Sxundyaxs
RegEx Demo
I have this string:
var s = '/channels/mtb/videos?page=2&per_page=100&fields=uri%2Cname%2Cdescription%2Cduration%2Cwidth%2Cheight%2Cprivacy%2Cpictures.sizes&sort=date&direction=asc&filter=embeddable&filter_embeddable=true'
I want to repace per_page number (in this case 100, but it can be any number from 1-100, maybe more?)
I can select first part of the string with:
var s1 = s.substr(0, s.lastIndexOf('per_page=')+9)
which give me:
/channels/mtb/videos?page=2&per_page=
but how would I select next '&' after that so I can replace number occurrence?
dont assume same order of parameters!
You can use following regex to replace the content you want.
regex:- /per_page=[\d]*/g(this is only for your requirement)
var new_no=12; //change 100 to 12
var x='/channels/mtb/videos?page=2&per_page=100&fields=uri%2Cname%2Cdescription%2Cduration%2Cwidth%2Cheight%2Cprivacy%2Cpictures.sizes&sort=date&direction=asc&filter=embeddable&filter_embeddable=true';
var y=x.replace(/per_page=[\d]*/g,'per_page='+new_no);
console.log(y);
Explanation:-
/per_page=[\d]*/g
/ ----> is for regex pattern(it inform that from next character onward whatever it encounter will be regex pattern)
per_page= ----> try to find 'per_page=' in string
[\d]* ----> match 0 or more digit (it match until non digit encounter)
/g ---->/ to indicate end of regex pattern and 'g' is for global means find in all string(not only first occurrence)
Use replace with a regular expression to find the numbers after the text per_page=. Like this:
s.replace(/per_page=\d+/,"per_page=" + 33)
Replace the 33 with the number you want.
Result:
"/channels/mtb/videos?page=2&per_page=33&fields=uri%2Cname%2Cdescription%2Cduration%2Cwidth%2Cheight%2Cprivacy%2Cpictures.sizes&sort=date&direction=asc&filter=embeddable&filter_embeddable=true"
Start with the index from the lastIndexOf-per_page instead of 0.
Get the index of the first & and create a substr s2 to the end.
Then concat s1 + nr + s2.
I would not use regex, because it is much slower for this simple stuff.
With Array.filter you can do this, where one split the text into key/value pairs, and filter out the one that starts with per_page=.
Stack snippet
var s = '/channels/mtb/videos?page=2&per_page=100&fields=uri%2Cname%2Cdescription%2Cduration%2Cwidth%2Cheight%2Cprivacy%2Cpictures.sizes&sort=date&direction=asc&filter=embeddable&filter_embeddable=true'
var kv_pairs = s.split('&');
var s2 = s.replace((kv_pairs.filter(w => w.startsWith('per_page=')))[0],'per_page=' + 123);
//console.log(s2);
var matches = /(.*\bper_page=)(\d+)(.*)/;
if (matches) {
s = matches[0] + newValue + matches[2];
}
I am trying to remove some spaces from a few dynamically generated strings. Which space I remove depends on the length of the string. The strings change all the time so in order to know how many spaces there are, I iterate over the string and increment a variable every time the iteration encounters a space. I can already remove all of a specific type of character with str.replace(' ',''); where 'str' is the name of my string, but I only need to remove a specific occurrence of a space, not all the spaces. So let's say my string is
var str = "Hello, this is a test.";
How can I remove ONLY the space after the word "is"? (Assuming that the next string will be different so I can't just write str.replace('is ','is'); because the word "is" might not be in the next string).
I checked documentation on .replace, but there are no other parameters that it accepts so I can't tell it just to replace the nth instance of a space.
If you want to go by indexes of the spaces:
var str = 'Hello, this is a test.';
function replace(str, indexes){
return str.split(' ').reduce(function(prev, curr, i){
var separator = ~indexes.indexOf(i) ? '' : ' ';
return prev + separator + curr;
});
}
console.log(replace(str, [2,3]));
http://jsfiddle.net/96Lvpcew/1/
As it is easy for you to get the index of the space (as you are iterating over the string) , you can create a new string without the space by doing:
str = str.substr(0, index)+ str.substr(index);
where index is the index of the space you want to remove.
I came up with this for unknown indices
function removeNthSpace(str, n) {
var spacelessArray = str.split(' ');
return spacelessArray
.slice(0, n - 1) // left prefix part may be '', saves spaces
.concat([spacelessArray.slice(n - 1, n + 1).join('')]) // middle part: the one without the space
.concat(spacelessArray.slice(n + 1)).join(' '); // right part, saves spaces
}
Do you know which space you want to remove because of word count or chars count?
If char count, you can Rafaels Cardoso's answer,
If word count you can split them with space and join however you want:
var wordArray = str.split(" ");
var newStr = "";
wordIndex = 3; // or whatever you want
for (i; i<wordArray.length; i++) {
newStr+=wordArray[i];
if (i!=wordIndex) {
newStr+=' ';
}
}
I think your best bet is to split the string into an array based on placement of spaces in the string, splice off the space you don't want, and rejoin the array into a string.
Check this out:
var x = "Hello, this is a test.";
var n = 3; // we want to remove the third space
var arr = x.split(/([ ])/); // copy to an array based on space placement
// arr: ["Hello,"," ","this"," ","is"," ","a"," ","test."]
arr.splice(n*2-1,1); // Remove the third space
x = arr.join("");
alert(x); // "Hello, this isa test."
Further Notes
The first thing to note is that str.replace(' ',''); will actually only replace the first instance of a space character. String.replace() also accepts a regular expression as the first parameter, which you'll want to use for more complex replacements.
To actually replace all spaces in the string, you could do str.replace(/ /g,""); and to replace all whitespace (including spaces, tabs, and newlines), you could do str.replace(/\s/g,"");
To fiddle around with different regular expressions and see what they mean, I recommend using http://www.regexr.com
A lot of the functions on the JavaScript String object that seem to take strings as parameters can also take regular expressions, including .split() and .search().
I have a url with many delimiters '/'.
I want to find the string after the last delimiter. How can I write a javascript code?
for eg if my url is
localhost/sample/message/invitation/create/email
I want to display 'email' as my output.
var last = input.split("/").pop();
Simples!
Splitting on a regex that matches spaces or hyphens and taking the last element
var lw = function(v) {
return (""+v).replace(/[\s-]+$/,'').split(/[\s-]/).pop();
};
lw('This is a test.'); // returns 'test.'
lw('localhost/sample/message/invitation/create/email,'); // returns 'email,'
var url="localhost/sample/message/invitation/create/email";
url.split("/").pop()
or
var last=$(url.split("/")).last();
Usng simple regex
var str = "localhost/sample/message/invitation/create/email";
var last = str.match(/[^/]*$/)[0]";
Above regex return all character after last "/"
I'm trying to split a string into an array based on the second occurrence of the symbol _
var string = "this_is_my_string";
I want to split the string after the second underscore. The string is not always the same but it always has 2 or more underscores in it. I always need it split on the second underscore.
In the example string above I would need it to be split like this.
var split = [this_is, _my_string];
var string = "this_is_my_string";
var firstUnderscore = string.indexOf('_');
var secondUnderscore = string.indexOf('_', firstUnderscore + 1);
var split = [string.substring(0, secondUnderscore),
string.substring(secondUnderscore)];
Paste it into your browser's console to try it out. No need for a jsFiddle.
var string = "this_is_my_string";
var splitChar = string.indexOf('_', string.indexOf('_') + 1);
var result = [string.substring(0, splitChar),
string.substring(splitChar, string.length)];
This should work.
var str = "this_is_my_string";
var matches = str.match(/(.*?_.*?)(_.*)/); // MAGIC HAPPENS HERE
var firstPart = matches[1]; // this_is
var secondPart = matches[2]; // _my_string
This uses regular expressions to find the first two underscores, and captures the part up to it and the part after it. The first subexpression, (.*?_.*?), says "any number of characters, an underscore, and again any number of characters, keeping the number of characters matched as small as possible, and capture it". The second one, (_.*) means "match an underscore, then any number of characters, as much of them as possible, and capture it". The result of the match function is an array starting with the full matched region, followed by the two captured groups.
I know this post is quite old... but couldn't help but notice that no one provided a working solution. Here's one that works:
String str = "this_is_my_string";
String undScore1 = str.split("_")[0];
String undScore2 = str.split("_")[1];
String bothUndScores = undScore1 + "_" + undScore2 + "_";
String allElse = str.split(bothUndScores)[1];
System.out.println(allElse);
This is assuming you know there will always be at least 2 underscores - "allElse" returns everything after the second occurrence.