I'm working on my final project of the Winter 2017 quarter to demonstrate how to use Regular Expressions in both C# and JavaScript code behind pages. I've got the C# version of my demonstration program done, but the JavaScript version is making me pull what little hair I have left on my head out (no small achievement since I got a fresh buzz cut this morning!). The problem involves not getting any output after applying a Regular Expression in a While loop to get each instance of the expression and printing it out.
On my HTML page I have an input textarea, seven radio buttons, an output textarea, and two buttons underneath (one button is to move the output text to the input area to perform multiple iterations of applying expressions, and the other button to clear all textareas for starting from scratch). Each radio button links to a function that applies a regular expression to the text in the input area. Five of my seven functions work; the sixth is the one I can't figure out, and the seventh is essentially the same but with a slightly different RegEx pattern, so if I fix the sixth function, the seventh function will be a snap.
(I tried to insert/upload a JPG of the front end, but the photo upload doesn't seem to be working. Hopefully you get the drift of what I've set up.)
Here are my problem children from my JS code behind:
// RegEx_Demo_JS.js - code behind for RegEx_Demo_JS
var inputString; // Global variable for the input from the input text box.
var pattern; // Global variable for the regular expression.
var result; // Global variable for the result of applying the regular expression to the user input.
// Initializes a new instance of the StringBuilder class
// and appends the given value if supplied
function StringBuilder()
{
var strings = [];
this.append = function (string)
{
string = verify(string);
if (string.length > 0) strings[strings.length] = string;
}
this.appendLine = function (string)
{
string = verify(string);
if (this.isEmpty())
{
if (string.length > 0) strings[strings.length] = string;
else return;
}
else strings[strings.length] = string.length > 0 ? "\r\n" + string : "\r\n";
}
this.clear = function () { strings = []; };
this.isEmpty = function () { return strings.length == 0; };
this.toString = function () { return strings.join(""); };
var verify = function (string)
{
if (!defined(string)) return "";
if (getType(string) != getType(new String())) return String(string);
return string;
}
var defined = function (el)
{
// Changed per Ryan O'Hara's comment:
return el != null && typeof(el) != "undefined";
}
var getType = function (instance)
{
if (!defined(instance.constructor)) throw Error("Unexpected object type");
var type = String(instance.constructor).match(/function\s+(\w+)/);
return defined(type) ? type[1] : "undefined";
}
}
Within the code of the second radio button (which will be the seventh and last function to complete), I tested the ScriptBuilder with data in a local variable, and it ran successfully and produced output into the output textarea. But I get no output from this next function that invokes a While loop:
function RegEx_Match_TheOnly_AllInstances()
{
inputString = document.getElementById("txtUserInput").value;
pattern = /(\s+the\s+)/ig; // Using an Flag (/i) to select either lowercase or uppercase version. Finds first occurrence either as a standalone word or inside a word.
//result = pattern.exec(inputString); // Finds the first index location
var arrResult; // Array for the results of the search.
var sb = getStringBuilder(); // Variable to hold iterations of the result and the text
while ((arrResult = pattern.exec(inputString)) !==null)
{
sb.appendLine = "Match: " + arrResult[0] ;
}
document.getElementById("txtRegExOutput").value = sb.toString();
/* Original code from C# version:
// string pattern = #"\s+(?i)the\s+"; // Same as above, but using Option construct for case insensitive search.
string pattern = #"(^|\s+)(?i)the(\W|\s+)";
MatchCollection matches = Regex.Matches(userTextInput, pattern);
StringBuilder outputString = new StringBuilder();
foreach (Match match in matches)
{
string outputRegExs = "Match: " + "\"" + match.Value + "\"" + " at index [" + match.Index + ","
+ (match.Index + match.Length) + "]" + "\n";
outputString.Append(outputRegExs);
}
txtRegExOutput.Text = outputString.ToString();
*/
} // End RegEx_Match_The_AllInstances
I left the commented code in to show what I had used in the C# code behind version to illustrate what I'm trying to accomplish.
The test input/string I used for this function is:
Don’t go there. If you want to be the Man, you have to beat The Man.
That should return two hits. Ideally, I want it to show the word that it found and the index where it found the word, but at this point I'd be happy to just get some output showing every instance it found, and then build on that with the index and possibly the lastIndex.
So, is my problem in my While loop, the way I'm applying the StringBuilder, or a combination of the two? I know the StringBuilder code works, at least when not being used in a loop and using some test data from the site I found that code. And the code for simply finding the first instance of "the" as a standalone or inside another word does work and returns output, but that doesn't use a loop.
I've looked through Stack Overflow and several other JavaScript websites for inspiration, but nothing I've tried so far has worked. I appreciate any help anyone can provide! (If you need me to post any other code, please advise and I'll be happy to oblige.)
Related
i could not make it as function.Please help.When i modified as function and add button,it not work.
i'm newbie in javascript.i would like study by the simple script.But for the below script when i try to add "function xxx()" it not working with input button.
I try to solve by my own with google...failed.
<script>
var myStr = "xxx yyy zzz";
var strArray = myStr.split(" ");
// Display array values on page
for(var i = 0; i < strArray.length; i++){
document.write("<p>" + strArray[i] + "</p>");
}
</script>
Break your code into blocks if you ever are stuck on something. So first you are trying to break a string into an array so that's your first block. Then your second block would be to write it to the page. So we have our code basically written out in our heads.
---Break string
---Display broken string
So to make a function we need to write a function first
myFunction = function(){
};
But to get the function to be modular we need to be able to pass in variables
So we'll add two variables one being the string to pass through and one being the location to inject the looped broken text.
myFunction = function(str, location){
};
Now we have to do something with these variables.
myFunction = function(str, location){
///test if str is a string
if(typeof(str) == "string")
{
var l = str.split(" "); /// here we're spliting the string into an array by every space
if(l.length >= 1) ///test if there's atleast one item
for(i=0;i<l.length;i++) ///simple for loop
location.innerHTML += "This is a part of str " + l[i] + "<br>" ///you can do anything here you want to do.
}
};
Now as you can see it's modular at it's lowest point, this can be as complex as you want it. here is a test you can try out and mess around with. https://jsfiddle.net/s8pytzm3/1/
Can somebody please help me with PigLatin? I'm trying to solve is problem here and my code works most of the time but I can't make some parts of it work.
For example when I give a string to the function like quiet or square, I want the function to take the qu part as 1 letter. So quiet would be ietquay and square would be aresquay..
Would it also be possible to make it work when I give it a long string with multiple words? Do the function on every word in the string basically..
My code so far:
const piglatin = string => {
let firstVowel = string.match(/[aeiou]/);
let firstPosition = string.indexOf(firstVowel);
if (firstPosition > 0) {
return string.slice(firstPosition) + string.slice(0, firstPosition) + 'ay';
}
return string + "ay";
}
World!
I'm trying to create a program in Javascript that takes the log of a number typed into an HTML input. Unfortunately i've encountered a problem where it wont accept the string with the .replace().
Its Function:
I.E: When log(10) is calculated, the function should first remove the first 4 char's "log(" next remove the last parenthesis ")" and then take the log of the no. between.
HTML includes style elements, button and input form and an output < DIV >.
//Function
function calculate()
{
var inputString = document.getElementById("inpstr");
var output = document.getElementById("output");
//TESTING CODE
/*
if (inputString.value.startsWith("log(").endsWith(")"))
{
console.log(output.innerHTML = inputString.value.substring(4, 20).replace(")", ""));
}
else
{
output.innerHTML = "false";
}
*/
//Math.log() calc *****DOESNT WORK*****
if (inputString.value.startsWith("log(").endsWith(")"))
{
output.innerHTML = Math.log(inputString.value.replace(")", "").substring(4, 20));
}
else
{
output.innerHTML = inputString.value;
}
event.preventDefault();
}
If someone can give me an effective solution that would be much appreciated.
Thanks,
Syntax
Since Math.log() accepts only number values and you're trying to pass a string to it, you should first parse this value into a float number and then pass it to the log function:
let val = parseFloat(inputString.value.replace(")", "").substring(4, 20));
output.innerHTML = Math.log(val);
I'm guessing I got downvoted for being lazy, so here is the quick info. Gonras got it right relating to what you want to extract, but he forgot to check that what's being input is actually a log.
That's where the regex below comes in handy! I'm matching the field to:
^ start of word, since we want to match the entire field.
log(
([-.\d])) any consecutive sequence () of numbers (\d), -, and '.', represented by the []. The \(...\) makes sure to save this inner part for later.
$ is end of word, see 1.
res will be null if there is no match. Otherwise, res[0] is the entire match (so the entire input field) and res[1] is the first 'capture group', at point 3 - which is presumably the number.
This of course fails for multiple "-" inside, or "." etc... so think it over.
//Function
function calculate()
{
var inputString = document.getElementById("inpstr");
var output = document.getElementById("output");
var res = /^log\(([-.\d]*)\)$/.exec(inputString.value);
if (res)
output.innerHTML = Math.log(res[1]);
else
output.innerHTML = res;
}
document.getElementById("output").innerHTML='start';
calculate()
<div id='output'></div>
<input id='inpstr' value='log(2.71828)'></input>
If I wanted to fix your if to supplement Gonras's solution:
if (inputString.value.startsWith("log(") && inputString.value.endsWith(")"))
Yours fails since startsWith() returns a boolean, which obviously doesn't have a endsWith function.
I've written an extension for firefox which highlights all words on a web page (excluding some words in a given list).
What i've noticed is that (besides that my extension is terribly slow) some web pages get "destroyed", more specifically the layout gets destroyed (particularly websites with overlay advertising or fancy drop-down menus).
My code wraps <span> tags around every "word", or to be precise around every token, because i'm splitting the text nodes with a whitespace as seperator.
So is it possible anyway to realize this task without destroying the page's layout?
I'm iterating over all text nodes, split them, and iterate over every token.
When the token is in my list, i don't highlight it, else i wrap the <span> tag around it.
So any suggestions how this could be done faster would be helpful, too.
Here are some screenshots for a correctly highlighted and a not correctly highlighted web page:
right:
en.wikipedia.org before highlighting,
en.wikipedia.org after highlighting.
wrong:
developer.mozilla.org before highlighting,
developer.mozilla.org after highlighting.
OK. Study this code. It searches for all instances of "is" and highlights if it is not surrounded by word characters. Put this in your scratchpad while this tab is focused. You will see that words like "List" and other words containing "Is" are no highlighted, but all the "Is"'s are.
I basically made an addon here for you. You can now release this as an addon called RegEx FindBar and take all the credit....
var doc = gBrowser.contentDocument;
var ctrler = _getSelectionController(doc.defaultView);
var searchRange = doc.createRange();
searchRange.selectNodeContents(doc.documentElement);
let startPt = searchRange.cloneRange();
startPt.collapse(true);
let endPt = searchRange.cloneRange();
endPt.collapse(false);
let retRane = null;
let finder = Cc["#mozilla.org/embedcomp/rangefind;1"].createInstance().QueryInterface(Ci.nsIFind);
finder.caseSensitive = false;
var i = 0;
while (retRange = finder.Find('is', searchRange, startPt, endPt)) {
i++;
var stCont = retRange.startContainer;
var endCont = retRange.endContainer;
console.log('retRange(' + i + ') = ', retRange);
console.log('var txt = retRange.commonAncestorContainer.data',retRange.commonAncestorContainer.data);
//now test if one posiion before startOffset and one position after endOffset are WORD characters
var isOneCharBeforeStCharWordChar; //var that holds if the character before the start character is a word character
if (retRange.startOffset == 0) {
//no characters befor this characte so obviously not a word char
isOneCharBeforeStCharWordChar = false;
} else {
var oneCharBeforeStChar = stCont.data.substr(retRange.startOffset-1,1);
if (/\w/.test(oneCharBeforeStChar)) {
isOneCharBeforeStCharWordChar = true;
} else {
isOneCharBeforeStCharWordChar = false;
}
console.log('oneCharBeforeStChar',oneCharBeforeStChar);
}
var isOneCharAfterEndCharWordChar; //var that holds if the character before the start character is a word character
if (retRange.endOffset == endCont.length - 1) {
//no characters after this characte so obviously not a word char
isOneCharAfterEndCharWordChar = false;
} else {
var oneCharAferEndChar = endCont.data.substr(retRange.endOffset,1); //no need to subtract 1 from endOffset, it takes into account substr 2nd arg is length and is treated like length I THINK
if (/\w/.test(oneCharAferEndChar)) {
isOneCharAfterEndCharWordChar = true;
} else {
isOneCharAfterEndCharWordChar = false;
}
console.log('oneCharAferEndChar',oneCharAferEndChar);
}
if (isOneCharBeforeStCharWordChar == false && isOneCharAfterEndCharWordChar == false) {
//highlight it as surrounding characters are no word characters
_highlightRange(retRange, ctrler);
console.log('highlighted it as it was not surrounded by word charactes');
} else {
console.log('NOT hilte it as it was not surrounded by word charactes');
}
//break;
startPt = retRange.cloneRange();
startPt.collapse(false);
}
/*********************/
function _getEditableNode(aNode) {
while (aNode) {
if (aNode instanceof Ci.nsIDOMNSEditableElement)
return aNode.editor ? aNode : null;
aNode = aNode.parentNode;
}
return null;
}
function _highlightRange(aRange, aController) {
let node = aRange.startContainer;
let controller = aController;
let editableNode = this._getEditableNode(node);
if (editableNode)
controller = editableNode.editor.selectionController;
let findSelection = controller.getSelection(Ci.nsISelectionController.SELECTION_FIND);
findSelection.addRange(aRange);
if (editableNode) {
// Highlighting added, so cache this editor, and hook up listeners
// to ensure we deal properly with edits within the highlighting
if (!this._editors) {
this._editors = [];
this._stateListeners = [];
}
let existingIndex = this._editors.indexOf(editableNode.editor);
if (existingIndex == -1) {
let x = this._editors.length;
this._editors[x] = editableNode.editor;
this._stateListeners[x] = this._createStateListener();
this._editors[x].addEditActionListener(this);
this._editors[x].addDocumentStateListener(this._stateListeners[x]);
}
}
}
function _getSelectionController(aWindow) {
// display: none iframes don't have a selection controller, see bug 493658
if (!aWindow.innerWidth || !aWindow.innerHeight)
return null;
// Yuck. See bug 138068.
let docShell = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIWebNavigation)
.QueryInterface(Ci.nsIDocShell);
let controller = docShell.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsISelectionDisplay)
.QueryInterface(Ci.nsISelectionController);
return controller;
}
Oh edit my solution out, will update with proper solution, I see you want to highlight all words
This is the code how firefox highlights stuff without changing document: Finder.jsm - _highlight function. You will have to copy this and use it for the whole document, if you need help let me know and I'll do it.
Here was my solution to highlight all matches of single word: https://stackoverflow.com/a/22206366/1828637
Here man this is how you are going to highlight the whole document, I didn't finish the snippet but this is the start of it: Gist - HighlightTextInDocument
Here's the copy paste answer to highlight everything in the document. As you learn more about it share with us, like how you can highlight with a different color, right now its all pink O_O
function _getEditableNode(aNode) {
while (aNode) {
if (aNode instanceof Ci.nsIDOMNSEditableElement)
return aNode.editor ? aNode : null;
aNode = aNode.parentNode;
}
return null;
}
function _highlightRange(aRange, aController) {
let node = aRange.startContainer;
let controller = aController;
let editableNode = this._getEditableNode(node);
if (editableNode)
controller = editableNode.editor.selectionController;
let findSelection = controller.getSelection(Ci.nsISelectionController.SELECTION_FIND);
findSelection.addRange(aRange);
if (editableNode) {
// Highlighting added, so cache this editor, and hook up listeners
// to ensure we deal properly with edits within the highlighting
if (!this._editors) {
this._editors = [];
this._stateListeners = [];
}
let existingIndex = this._editors.indexOf(editableNode.editor);
if (existingIndex == -1) {
let x = this._editors.length;
this._editors[x] = editableNode.editor;
this._stateListeners[x] = this._createStateListener();
this._editors[x].addEditActionListener(this);
this._editors[x].addDocumentStateListener(this._stateListeners[x]);
}
}
}
function _getSelectionController(aWindow) {
// display: none iframes don't have a selection controller, see bug 493658
if (!aWindow.innerWidth || !aWindow.innerHeight)
return null;
// Yuck. See bug 138068.
let docShell = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsIWebNavigation)
.QueryInterface(Ci.nsIDocShell);
let controller = docShell.QueryInterface(Ci.nsIInterfaceRequestor)
.getInterface(Ci.nsISelectionDisplay)
.QueryInterface(Ci.nsISelectionController);
return controller;
}
var doc = gBrowser.contentDocument;
var searchRange = doc.createRange();
searchRange.selectNodeContents(doc.documentElement);
_highlightRange(searchRange,_getSelectionController(gBrowser.contentWindow))
#jervis, I can't make a comment on your comment under #Noitidart code as I don't have 50rep yet. So I have to post here.
Re:
I did it with 'gFindBar._highlightDoc(true, word)' now. I'm using firefox 17, so i dont know if gFindBar is state of the art. – jervis 40 mins ago
But I tested his code and and it works.
Don't use gFindBar.
Copy it and then paste it into your Scratchpad.
Why are you using gFindBar._highlightDoc(true, word) ? I thoght you wanted to highlight everything in the document? Where did you get _highlightDoc from? I don't see that anywhere in #Noitidart's code.
Regading yoru comment on iterate all words and use gFindBar._highlightDoc:
I did it with 'gFindBar._highlightDoc(true, word)' now. I'm using firefox 17, so i dont know if gFindBar is state of the art. – jervis 39 mins ago
Dude why do that.... I saw #Noitidart posted a per word solution on the linked topic: gBrowser.tabContainer.childNodes[0].linkedBrowser.finder.highlight(true, 'YOUR_WORD_HERE'); that is extremely easy, one line and no need to create text nodes spans or anything. You have to run this code on each tab you want to highlight in.
I'm struggling with a ExtJS 4.1.1 grid that has editable cells (CellEditing plugin).
A person should be able to type a mathematic formula into the cell and it should generate the result into the field's value. For example: If a user types (320*10)/4 the return should be 800. Or similar if the user types (320m*10cm)/4 the function should strip the non-mathematical characters from the formula and then calculate it.
I was looking to replace (or match) with a RegExp, but I cannot seem to get it to work. It keeps returning NaN and when I do console.log(e.value); it returns only the originalValue and not the value that I need.
I don't have much code to attach:
onGridValidateEdit : function(editor,e,opts) {
var str = e.value.toString();
console.log(str);
var strCalc = str.match(/0-9+-*\/()/g);
console.log(strCalc);
var numCalc = Number(eval(strCalc));
console.log(numCalc);
return numCalc;
},
Which returns: str=321 strCalc=null numCalc=0 when I type 321*2.
Any help appreciated,
GR.
Update:
Based on input by Paul Schroeder, I created this:
onGridValidateEdit : function(editor,e,opts) {
var str = e.record.get(e.field).toString();
var strCalc = str.replace(/[^0-9+*-/()]/g, "");
var numCalc = Number(eval(strCalc));
console.log(typeof numCalc);
console.log(numCalc);
return numCalc;
},
Which calculates the number, but I am unable to print it back to the grid itself. It shows up as "NaN" even though in console it shows typeof=number and value=800.
Final code:
Here's the final code that worked:
onGridValidateEdit : function(editor,e,opts) {
var fldName = e.field;
var str = e.record.get(fldName).toString();
var strCalc = str.replace(/[^0-9+*-/()]/g, "");
var numCalc = Number(eval(strCalc));
e.record.set(fldName,numCalc);
},
Lets break this code down.
onGridValidateEdit : function(editor,e,opts) {
var str = e.value.toString();
What listener is this code being used in? This is very important for us to know, here's how I set up my listeners in the plugin:
listeners: {
edit: function(editor, e){
var record = e.record;
var str = record.get("your data_index of the value");
}
}
Setting it up this way works for me, So lets move on to:
var strCalc = str.match(/0-9+-*\/()/g);
console.log(strCalc);
at which point strCalc=null, this is also correct. str.match returns null because your regex does not match anything in the string. What I think you want to do instead is this:
var strCalc = str.replace(/[^0-9+*-]/g, "");
console.log(strCalc);
This changes it to replace all characters in the string that aren't your equation operators and numbers. After that I think it should work for whole numbers. I think that you may actually want decimal numbers too, but I can't think of the regex for that off the top of my head (the . needs to be escaped somehow), but it should be simple enough to find in a google search.