Javascript method to convert string value - javascript

Can someone please help me to write a JS method which takes a String value like
/Content/blockDiagram/0/bundle/0/selectedBundle
/Content/blockDiagram/1/bundle/1/selectedBundle
/Content/blockDiagram/0/bundle
and convert it to
/Content/blockDiagram[1]/bundle[1]/selectedBundle
/Content/blockDiagram[2]/bundle[2]/selectedBundle
/Content/blockDiagram[1]/bundle
It is basically taking the number in the path and increment it by 1 and then changing the structure of the string.
My attempt
function setReplicantPartListOptions(list) {
list = "/" + list;
var index = list.lastIndexOf("/");
var tempString = list.substring(0, index);
var index2 = tempString.lastIndexOf("/");
var initialString = list.substring(0, index2);
var result = tempString.substring(index2 + 1, index) var middlevalue = parseFloat(result) + 1
var lastString = list.substring(index, list.length);
list = initialString + "[" + middlevalue + "]" + lastString;
return list;
}

simple regular expression with capture group with replace
var str = "/Content/blockDiagram/0/bundle/0/selectedBundle"
var updated = str.replace(/\/(\d+)/g, function (m, num) {
var next = +num + 1; // convert string to number and add one
return "[" + next + "]"; //return the new string
})
console.log(updated)

String.replace(RegExp, callback(match, contents)) is the callback version of String.replace().
In my case, the first parameter of callback function is the result/match. It takes the match and converts it to number using + operator, and then increment it by one. Finally, I add [ ] around the value and return it!
let str = "/Content/blockDiagram/0/bundle/0/selectedBundle"
console.log(
str.replace(/\b\d+\b/g, match => `[${ +match + 1 }]`)
);

var str = "/Content/blockDiagram/0/bundle/0/selectedBundle"
console.log(
str.replace(/\/(\d+)\//g, function(_,num) { return `[${++num}]`})
)

Related

Removing multiple indexes from array in Javascript

I am trying to write a function that takes 3 arguments and then return a string after removing the given indexes. Here is my code:
var name = {};
function strCut(arg1, arg2, arg3){
if(arg1 === 'Jordi')
arg1.splice(0, 1) && arg1.splice(4,1)
return arg1
}
strCut('Jordi', 0, 4)
//I am trying to splice the "J" and the "i"
to return an array of name = ord
Try this function:
function strCut(arg1, arg2, arg3) {
if (arg1 === 'Jordi') {
var temp = arg1.split("");
delete temp[arg2]
delete temp[arg3]
}
// return temp.join("") if you want to return a string.
return temp.join("").split("");
}
console.log(strCut('Jordi', 0, 4))
Look into Join and Split functions.
I think you mean a String not Array? If you need to convert a String to Array you can use str.split('');
Also I think your function should use arg2 and arg3 instead of constant 0 and 4?
You cannot concatenate strings or arrays using && if that is what you intend, you should use the + operator for strings and .concat or ... (spread operator) for arrays.
The issue is that when you remove one index, the other one gets decreased by one, an easy solution for that is to remove the larger index first.
Here is your code if it is a String:
var name = {};
function strCut(str, firstIndex, secondIndex){
var largerIndex = Math.max(firstIndex, secondIndex);
var smallerIndex = Math.min(firstIndex, secondIndex);
str = str.slice(0, largerIndex) + str.slice(largerIndex + 1); //Removing the larger index
str = str.slice(0, smallerIndex) + str.slice(smallerIndex + 1); //Removing the smaller index
return str;
}
strCut('Jordi', 0, 4);
Here is your code if it is an Array:
var name = {};
function strCut(str, firstIndex, secondIndex){
var largerIndex = Math.max(firstIndex, secondIndex);
var smallerIndex = Math.min(firstIndex, secondIndex);
str = str.slice(0, largerIndex).concat(str.slice(largerIndex + 1)); //Removing the larger index
str = str.slice(0, smallerIndex).concat(str.slice(smallerIndex + 1)); //Removing the smaller index
return str;
}
strCut('Jordi'.split(''), 0, 4); //The string gets passed as an array this way

How can I get this result in RegEx using Javascript

If my entry is "001.1-2016", I want "001.2-2016"
If my entry is "001.8-2015", I want "001.9-2016"
If my entry is "001.12-2014", I want "001.13-2016"
If my entry is "001.123-2016", I want "001.124-2016"
I tried a regex like this:
([0-9]{3}\.)(.*)(\-[0-9]{4})
but this get all, I want only the middle.
Your regex (\[0-9\]{3}\.)(.*)(\-\[0-9\]{4}) works fine, you just need to get the second captured group result.
var arr = ["001.1-2016", "001.8-2015", "001.12-2014", "001.123-2016"];
var regex = /([0-9]{3}\.)(.*)(\-[0-9]{4})/;
arr.forEach(function(str) {
document.body.innerHTML += str.match(regex)[2] + '<br />';
});
You can use String#split and parseInt.
var value = "001.12-2014";
var num = parseInt(value.split('.')[1], 10);
var value = "001.12-2014";
var num = parseInt(value.split('.')[1], 10);
document.body.innerHTML = num;
Using Regex
var value = "001.12-2014";
var num = value.match(/.*?\.(\d+)/)[1];
var value = "001.12-2014";
var num = (value.match(/.*?\.(\d+)/) || [])[1];
document.body.innerHTML = num;
I need just add +1 in this number, eg. "001.12-2014" >>> "001.13-2014" or "001.123-2014" >>> "001.124-2014"
var arr = ["001.1-2016", "001.8-2015", "001.12-2014", "001.123-2016"];
arr = arr.map(e => e.replace(/\.(\d+)/, ($0, $1) => '.' + (1 + +$1)));
document.body.innerHTML = arr;
To increment the number by 1 you can use String#replace
document.getElementById('input').addEventListener('keyup', function() {
var value = this.value;
value = value.replace(/\.(\d+)/, function($0, $1) {
return '.' + (1 + +($1 || 0));
});
document.getElementById('output').innerHTML = value;
}, false);
<input type="text" id="input" />
<pre id="output"></pre>
The regex pattern could be
/[0-9]+\.([0-9]+)\-[0-9]+/g
if you do not concern the number format before . and after -
You can test it on here.
Try to use split method .The split() method splits a String object into an array of strings by separating the string into substrings.
<script>
function myFunction() {
var str = "001.12-2014";
var res = new Array();
res=str.split(".");
var finalres=res[1].split("-",1);
document.getElementById("demo").innerHTML = finalres;
}
</script>
Output:
this matches all 4 (find the decimal and take one or more digits that follow):
/\.(\d+)/g
# https://regex101.com/r/qG2mX7/4

Pattern match in javascript

In the below code Im not getting the right result. How can I can do pattern match in javascript?
function getPathValue(url, input) {
console.log("this is path key :"+input);
url = url.replace(/%7C/g, '|');
var inputarr = input.split("|");
if (inputarr.length > 1)
input = '\\b' + inputarr[0] + '\n|' + inputarr[1] + '\\b';
else
input = '\\b' + input + '\\b';
var field = url.search(input);
var slash1 = url.indexOf("/", field);
var slash2 = url.indexOf("/", slash1 + 1);
if (slash2 == -1)
slash2 = url.indexOf("?");
if (slash2 == -1)
slash2 = url.length;
console.log("this is path param value :"+url.substring(slash1 + 1, slash2));
return url.substring(slash1 + 1, slash2);
}
getPathValue("http://localhost/responsePath/mountainwithpassid|accesscode/100/mountainwithpassid|passid/1","mountainwithpassid|passid")
Im getting the below output
If I pass mountainwithpassid|accesscode as input Im getting output as
100. Same way if I pass
key :mountainwithpassid|passid value :100 // Expected output 1
If your intention is to simply retrieve the value in the path that follows the input (contained within '/') then you can achieve this with a simpler regular expression. First you will need a method to escape your input string since it contains a pipe character '|' which is translated as OR in regex.
You can use this (taken from https://stackoverflow.com/a/3561711):
RegExp.escape= function(s) {
return s.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
};
Then your getPathValue function can look something like:
function getPathValue(url, input) {
var pathValue = null;
var escapedInput = RegExp.escape(input);
// The RegExp below extracts the value that follows the input and
// is contained within '/' characters (the last '/' is optional)
var pathValueRegExp = new RegExp(".*" + escapedInput + "/([^/]+)/?.*", 'g');
if (pathValueRegExp.test(url)) {
pathValue = url.replace(pathValueRegExp, '$1');
}
return pathValue;
}
You will also need to think about how you handle errors - in the example a null value is returned if no match is found.
I'm trying to understand the question. Given a URL of:
"http://localhost/responsePath/mountainwithpassid|accesscode/100/mountainwithpassid|passid/1"
and an argument of:
"mountainwithpassid|passid"
you expect a return value of:
"1"
An argument of
"mountainwithpassid|accesscode"
should return:
"100"
Is that correct? If so (and I'm not certain it is) then the following may suit:
function getPathValue(url, s) {
var x = url.indexOf(s);
if (x != -1) {
return url.substr(x).split('/')[1];
}
}
var url = "http://localhost/responsePath/mountainwithpassid|accesscode/100/mountainwithpassid|passid/1";
var x = "mountainwithpassid|passid";
var y = "mountainwithpassid|accesscode";
console.log(getPathValue(url, x)); // 1
console.log(getPathValue(url, y)); // 100

replace HTML text with incrementing numbers in javascript

I have a bunch of text with no HTML, and I'm trying to find all replace all instances of String with <span id="x">String</span>
The catch is I'm trying to increment x every time to get a bunch of uniquely identifiable spans rather then identical ones.
I have no problem getting all instances of String, but for the life of me I can't get the increment to work. All help I can find seems to be directed towards doing the opposite of this.
Any ideas what I can do or where else to turn for help?
EDIT:
This is targeting a div with ID 'result' that contains only text.
var target = "String";
var X = //the number I was trying to increment
var re = new RegExp(" " + target + " ","g");
document.getElementById('result').innerHTML = document.getElementById('result').innerHTML.replace(re, '<span id="' + X + '">' + target + '</span>');
I'm guessing you are using a regex, which is fine, but you can specify a function as the second parameter to replace and do your logic there.
The MDN documentation for doing this is here - https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/replace#Specifying_a_function_as_a_parameter
You could use something like this:
http://jsfiddle.net/gjrCN/2/
function replacer(orig, target) {
var x = 0;
var re = new RegExp(target, "g");
var ret = orig.replace(re, function (match) {
return "<span id='" + (++x) + "'>" + match + "</span>";
});
return ret;
}
var example = "String Stringasdf String2344 String";
var replaced = replacer(example, "String");
console.log(replaced);
You can change ++x to x++ if you want the counting to start at 0 instead of 1.
With reference to these docs.
You can pass a function to the String.replace method would allow you to increment a counter with each call and use that to set your ID:
var forReplacements = "I do like a String that's a nice long String with Strings in it";
var incrementer = (function() {
var counter = -1;
var fn = function(match) {
counter++;
return "<span id='"+counter+"'>"+match+"</span>";
};
fn.reset = function() {
counter = -1;
}
return fn;
}());
var newString = forReplacements.replace(/String/g, incrementer )
See this fiddle to see it in action

How do I replace a character at a particular index in JavaScript?

I have a string, let's say Hello world and I need to replace the char at index 3. How can I replace a char by specifying a index?
var str = "hello world";
I need something like
str.replaceAt(0,"h");
In JavaScript, strings are immutable, which means the best you can do is to create a new string with the changed content and assign the variable to point to it.
You'll need to define the replaceAt() function yourself:
String.prototype.replaceAt = function(index, replacement) {
return this.substring(0, index) + replacement + this.substring(index + replacement.length);
}
And use it like this:
var hello = "Hello World";
alert(hello.replaceAt(2, "!!")); // He!!o World
There is no replaceAt function in JavaScript. You can use the following code to replace any character in any string at specified position:
function rep() {
var str = 'Hello World';
str = setCharAt(str,4,'a');
alert(str);
}
function setCharAt(str,index,chr) {
if(index > str.length-1) return str;
return str.substring(0,index) + chr + str.substring(index+1);
}
<button onclick="rep();">click</button>
You can't. Take the characters before and after the position and concat into a new string:
var s = "Hello world";
var index = 3;
s = s.substring(0, index) + 'x' + s.substring(index + 1);
str = str.split('');
str[3] = 'h';
str = str.join('');
There are lot of answers here, and all of them are based on two methods:
METHOD1: split the string using two substrings and stuff the character between them
METHOD2: convert the string to character array, replace one array member and join it
Personally, I would use these two methods in different cases. Let me explain.
#FabioPhms: Your method was the one I initially used and I was afraid that it is bad on string with lots of characters. However, question is what's a lot of characters? I tested it on 10 "lorem ipsum" paragraphs and it took a few milliseconds. Then I tested it on 10 times larger string - there was really no big difference. Hm.
#vsync, #Cory Mawhorter: Your comments are unambiguous; however, again, what is a large string? I agree that for 32...100kb performance should better and one should use substring-variant for this one operation of character replacement.
But what will happen if I have to make quite a few replacements?
I needed to perform my own tests to prove what is faster in that case. Let's say we have an algorithm that will manipulate a relatively short string that consists of 1000 characters. We expect that in average each character in that string will be replaced ~100 times. So, the code to test something like this is:
var str = "... {A LARGE STRING HERE} ...";
for(var i=0; i<100000; i++)
{
var n = '' + Math.floor(Math.random() * 10);
var p = Math.floor(Math.random() * 1000);
// replace character *n* on position *p*
}
I created a fiddle for this, and it's here.
There are two tests, TEST1 (substring) and TEST2 (array conversion).
Results:
TEST1: 195ms
TEST2: 6ms
It seems that array conversion beats substring by 2 orders of magnitude! So - what the hell happened here???
What actually happens is that all operations in TEST2 are done on array itself, using assignment expression like strarr2[p] = n. Assignment is really fast compared to substring on a large string, and its clear that it's going to win.
So, it's all about choosing the right tool for the job. Again.
Work with vectors is usually most effective to contact String.
I suggest the following function:
String.prototype.replaceAt=function(index, char) {
var a = this.split("");
a[index] = char;
return a.join("");
}
Run this snippet:
String.prototype.replaceAt=function(index, char) {
var a = this.split("");
a[index] = char;
return a.join("");
}
var str = "hello world";
str = str.replaceAt(3, "#");
document.write(str);
In Javascript strings are immutable so you have to do something like
var x = "Hello world"
x = x.substring(0, i) + 'h' + x.substring(i+1);
To replace the character in x at i with 'h'
function dothis() {
var x = document.getElementById("x").value;
var index = document.getElementById("index").value;
var text = document.getElementById("text").value;
var length = document.getElementById("length").value;
var arr = x.split("");
arr.splice(index, length, text);
var result = arr.join("");
document.getElementById('output').innerHTML = result;
console.log(result);
}
dothis();
<input id="x" type="text" value="White Dog" placeholder="Enter Text" />
<input id="index" type="number" min="0"value="6" style="width:50px" placeholder="index" />
<input id="length" type="number" min="0"value="1" style="width:50px" placeholder="length" />
<input id="text" type="text" value="F" placeholder="New character" />
<br>
<button id="submit" onclick="dothis()">Run</button>
<p id="output"></p>
This method is good for small length strings but may be slow for larger text.
var x = "White Dog";
var arr = x.split(""); // ["W", "h", "i", "t", "e", " ", "D", "o", "g"]
arr.splice(6, 1, 'F');
/*
Here 6 is starting index and 1 is no. of array elements to remove and
final argument 'F' is the new character to be inserted.
*/
var result = arr.join(""); // "White Fog"
One-liner using String.replace with callback (no emoji support):
// 0 - index to replace, 'f' - replacement string
'dog'.replace(/./g, (c, i) => i == 0? 'f': c)
// "fog"
Explained:
//String.replace will call the callback on each pattern match
//in this case - each character
'dog'.replace(/./g, function (character, index) {
if (index == 0) //we want to replace the first character
return 'f'
return character //leaving other characters the same
})
Generalizing Afanasii Kurakin's answer, we have:
function replaceAt(str, index, ch) {
return str.replace(/./g, (c, i) => i == index ? ch : c);
}
let str = 'Hello World';
str = replaceAt(str, 1, 'u');
console.log(str); // Hullo World
Let's expand and explain both the regular expression and the replacer function:
function replaceAt(str, index, newChar) {
function replacer(origChar, strIndex) {
if (strIndex === index)
return newChar;
else
return origChar;
}
return str.replace(/./g, replacer);
}
let str = 'Hello World';
str = replaceAt(str, 1, 'u');
console.log(str); // Hullo World
The regular expression . matches exactly one character. The g makes it match every character in a for loop. The replacer function is called given both the original character and the index of where that character is in the string. We make a simple if statement to determine if we're going to return either origChar or newChar.
var str = "hello world";
console.log(str);
var arr = [...str];
arr[0] = "H";
str = arr.join("");
console.log(str);
This works similar to Array.splice:
String.prototype.splice = function (i, j, str) {
return this.substr(0, i) + str + this.substr(j, this.length);
};
You could try
var strArr = str.split("");
strArr[0] = 'h';
str = strArr.join("");
this is easily achievable with RegExp!
const str = 'Hello RegEx!';
const index = 11;
const replaceWith = 'p';
//'Hello RegEx!'.replace(/^(.{11})(.)/, `$1p`);
str.replace(new RegExp(`^(.{${ index }})(.)`), `$1${ replaceWith }`);
//< "Hello RegExp"
Using the spread syntax, you may convert the string to an array, assign the character at the given position, and convert back to a string:
const str = "hello world";
function replaceAt(s, i, c) {
const arr = [...s]; // Convert string to array
arr[i] = c; // Set char c at pos i
return arr.join(''); // Back to string
}
// prints "hallo world"
console.log(replaceAt(str, 1, 'a'));
You could try
var strArr = str.split("");
strArr[0] = 'h';
str = strArr.join("");
Check out this function for printing steps
steps(3)
// '# '
// '## '
// '###'
function steps(n, i = 0, arr = Array(n).fill(' ').join('')) {
if (i === n) {
return;
}
str = arr.split('');
str[i] = '#';
str = str.join('');
console.log(str);
steps(n, (i = i + 1), str);
}
#CemKalyoncu: Thanks for the great answer!
I also adapted it slightly to make it more like the Array.splice method (and took #Ates' note into consideration):
spliceString=function(string, index, numToDelete, char) {
return string.substr(0, index) + char + string.substr(index+numToDelete);
}
var myString="hello world!";
spliceString(myString,myString.lastIndexOf('l'),2,'mhole'); // "hello wormhole!"
If you want to replace characters in string, you should create mutable strings. These are essentially character arrays. You could create a factory:
function MutableString(str) {
var result = str.split("");
result.toString = function() {
return this.join("");
}
return result;
}
Then you can access the characters and the whole array converts to string when used as string:
var x = MutableString("Hello");
x[0] = "B"; // yes, we can alter the character
x.push("!"); // good performance: no new string is created
var y = "Hi, "+x; // converted to string: "Hi, Bello!"
You can extend the string type to include the inset method:
String.prototype.append = function (index,value) {
return this.slice(0,index) + value + this.slice(index);
};
var s = "New string";
alert(s.append(4,"complete "));
Then you can call the function:
You can concatenate using sub-string function at first select text before targeted index and after targeted index then concatenate with your potential char or string. This one is better
const myString = "Hello world";
const index = 3;
const stringBeforeIndex = myString.substring(0, index);
const stringAfterIndex = myString.substring(index + 1);
const replaceChar = "X";
myString = stringBeforeIndex + replaceChar + stringAfterIndex;
console.log("New string - ", myString)
or
const myString = "Hello world";
let index = 3;
myString = myString.substring(0, index) + "X" + myString.substring(index + 1);
I did a function that does something similar to what you ask, it checks if a character in string is in an array of not allowed characters if it is it replaces it with ''
var validate = function(value){
var notAllowed = [";","_",">","<","'","%","$","&","/","|",":","=","*"];
for(var i=0; i<value.length; i++){
if(notAllowed.indexOf(value.charAt(i)) > -1){
value = value.replace(value.charAt(i), "");
value = validate(value);
}
}
return value;
}
Here is a version I came up with if you want to style words or individual characters at their index in react/javascript.
replaceAt( yourArrayOfIndexes, yourString/orArrayOfStrings )
Working example: https://codesandbox.io/s/ov7zxp9mjq
function replaceAt(indexArray, [...string]) {
const replaceValue = i => string[i] = <b>{string[i]}</b>;
indexArray.forEach(replaceValue);
return string;
}
And here is another alternate method
function replaceAt(indexArray, [...string]) {
const startTag = '<b>';
const endTag = '</b>';
const tagLetter = i => string.splice(i, 1, startTag + string[i] + endTag);
indexArray.forEach(tagLetter);
return string.join('');
}
And another...
function replaceAt(indexArray, [...string]) {
for (let i = 0; i < indexArray.length; i++) {
string = Object.assign(string, {
[indexArray[i]]: <b>{string[indexArray[i]]}</b>
});
}
return string;
}
Here is my solution using the ternary and map operator. More readable, maintainable end easier to understand if you ask me.
It is more into es6 and best practices.
function replaceAt() {
const replaceAt = document.getElementById('replaceAt').value;
const str = 'ThisIsATestStringToReplaceCharAtSomePosition';
const newStr = Array.from(str).map((character, charIndex) => charIndex === (replaceAt - 1) ? '' : character).join('');
console.log(`New string: ${newStr}`);
}
<input type="number" id="replaceAt" min="1" max="44" oninput="replaceAt()"/>
My safe approach with negative indexes
/**
* #param {string} str
* #param {number} index
* #param {string} replacement
* #returns {string}
*/
static replaceAt (str, index, replacement)
{
if (index < 0) index = str.length + index
if (index < 0 || index >= str.length) throw new Error(`Index (${index}) out of bounds "${str}"`)
return str.substring(0, index) + replacement + str.substring(index + 1)
}
Use it like that:
replaceAt('my string', -1, 'G') // 'my strinG'
replaceAt('my string', 2, 'yy') // 'myyystring'
replaceAt('my string', 22, 'yy') // Uncaught Error: Index (22) out of bounds "my string"
Lets say you want to replace Kth index (0-based index) with 'Z'.
You could use Regex to do this.
var re = var re = new RegExp("((.){" + K + "})((.){1})")
str.replace(re, "$1A$`");
You can use the following function to replace Character or String at a particular position of a String. To replace all the following match cases use String.prototype.replaceAllMatches() function.
String.prototype.replaceMatch = function(matchkey, replaceStr, matchIndex) {
var retStr = this, repeatedIndex = 0;
for (var x = 0; (matchkey != null) && (retStr.indexOf(matchkey) > -1); x++) {
if (repeatedIndex == 0 && x == 0) {
repeatedIndex = retStr.indexOf(matchkey);
} else { // matchIndex > 0
repeatedIndex = retStr.indexOf(matchkey, repeatedIndex + 1);
}
if (x == matchIndex) {
retStr = retStr.substring(0, repeatedIndex) + replaceStr + retStr.substring(repeatedIndex + (matchkey.length));
matchkey = null; // To break the loop.
}
}
return retStr;
};
Test:
var str = "yash yas $dfdas.**";
console.log('Index Matched replace : ', str.replaceMatch('as', '*', 2) );
console.log('Index Matched replace : ', str.replaceMatch('y', '~', 1) );
Output:
Index Matched replace : yash yas $dfd*.**
Index Matched replace : yash ~as $dfdas.**
I se this to make a string proper case, that is, the first letter is Upper Case and all the rest are lower case:
function toProperCase(someString){
return someString.charAt(0).toUpperCase().concat(someString.toLowerCase().substring(1,someString.length));
};
This first thing done is to ensure ALL the string is lower case - someString.toLowerCase()
then it converts the very first character to upper case -someString.charAt(0).toUpperCase()
then it takes a substring of the remaining string less the first character -someString.toLowerCase().substring(1,someString.length))
then it concatenates the two and returns the new string -someString.charAt(0).toUpperCase().concat(someString.toLowerCase().substring(1,someString.length))
New parameters could be added for the replacement character index and the replacement character, then two substrings formed and the indexed character replaced then concatenated in much the same way.
The solution does not work for negative index so I add a patch to it.
String.prototype.replaceAt=function(index, character) {
if(index>-1) return this.substr(0, index) + character + this.substr(index+character.length);
else return this.substr(0, this.length+index) + character + this.substr(index+character.length);
}
"hello world".replace(/(.{3})./, "$1h")
// 'helho world'
The methods on here are complicated.
I would do it this way:
var myString = "this is my string";
myString = myString.replace(myString.charAt(number goes here), "insert replacement here");
This is as simple as it gets.

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