I'm checking an array of strings for a specific combination of patterns. I'm having trouble using Meteor's Match function and regex literal together. I want to check if the second string in the array is a url.
addCheck = function(line) {
var firstString = _.first(line);
var secondString = _.indexOf(line, 1);
console.log(secondString);
var urlRegEx = /((([A-Za-z]{3,9}:(?:\/\/)?)(?:[\-;:&=\+\$,\w]+#)?[A-Za-z0-9\.\-]+|(?:www\.|[\-;:&=\+\$,\w]+#)[A-Za-z0-9\.\-]+)((?:\/[\+~%\/\.\w\-]*)?\??(?:[\-\+=&;%#\.\w]*)#?(?:[\.\!\/\\\w]*))?)/g;
if ( firstString == "+" && Match.test(secondString, urlRegEx) === true ) {
console.log( "detected: + | line = " + line )
} else {
// do stuff if we don't detect a
console.log( "line = " + line );
}
}
Any help would be appreciated.
Match.test is used to test the structure of a variable. For example: "it's an array of strings, or an object including the field createdAt", etc.
RegExp.test on the other hand, is used to test if a given string matches a regular expression. That looks like what you want.
Try something like this instead:
if ((firstString === '+') && urlRegEx.test(secondString)) {
...
}
Related
I'm trying to match a string by its prefix that ends with a particular character. For example, if my string is "abcd" and ends in #, then any word which is a prefix of "abcd" should be matched as long as it ends with #. Here are some examples to help illustrate the pattern:
Input: "ab#" gives true (as "ab" is a prefix of "abcd" and end with a #).
Input: "abcd#" gives true (as "abcd" is a prefix of "abcd" and end with a #).
Input: "bc#" gives false (as "bc" is a not a prefix of "abcd" ).
Input: "ab#" gives false (while "ab" is a prefix of "abcd", it doesn't end with #) .
Input: "ac#" gives false (while "ac" is contained within "abcd", it doesn't begin with a prefix from "abcd") .
So far, I've managed to come up with the following expression which seems to be working fine:
/(abcd|abc|ab|a)#/
While this is working, it isn't very practical, as larger words of length n will make the expression quite large:
/(n|n-1|n-2| ... |1)#/
Is there a way to rewrite this expression so it is more scalable and concise?
Example of my attempt (in JS):
const regex = /(abcd|abc|ab|a)#/;
console.log(regex.test("abcd#")); // true
console.log(regex.test("ab#")); // true
console.log(regex.test("abc#")); // true
console.log(regex.test("abz#")); // false
console.log(regex.test("abc#")); // false
Edit: Some of the solutions provided are nice and do do what I'm after, however, for this particular question, I'm after a solution which uses pure regular expressions to match the prefix.
Just use String#startsWith and String#endsWith here:
String input = "abcd";
String prefix = "ab#";
if (input.startsWith(prefix.replaceAll("#$", "")) && prefix.endsWith("#")) {
System.out.println("MATCH");
}
else {
System.out.println("NO MATCH");
}
Edit: A JavaScript version of the above:
var input = "abcd";
var prefix = "ab#";
if (input.startsWith(prefix.replace(/#$/, "")) && prefix.endsWith("#")) {
console.log("MATCH");
}
else {
console.log("NO MATCH");
}
Try ^ab?c?d?#$
Explanation:
`^` - match beginning of a string
`b?` - match match zero or one `b`
Rest is analigocal to the above.
Demo
Here's a left field JavaScript option. Build and array of valid prefixes, use join on the array to make your regex pattern.
var validPrefixes = ["abcd",
"abc",
"ab",
"a",
"areallylongprefix"];
var regexp = new RegExp("^(" + validPrefixes.join("|") + ")#$");
console.log(regexp.test("abcd#"));// true
console.log(regexp.test("ab#")); // true
console.log(regexp.test("abc#")); // true
console.log(regexp.test("abz#")); // false
console.log(regexp.test("abc#")); // false
console.log(regexp.test("areallylongprefix#")); //true
This can be adapted to the language of tour choosing, also handy if your prefixes are dynamically retrieved from a database or similar.
Here's my c# attempt:
private static bool test(string v)
{
var pattern = "abcd#";
//No error handling
return v.EndsWith(pattern[pattern.Length-1])
&& pattern.Replace("#", "").StartsWith(v.Replace("#",""));
}
Console.WriteLine(test("abcd#")); // true
Console.WriteLine(test("ab#")); // true
Console.WriteLine(test("abc#")); // true
Console.WriteLine(test("abz#")); // false
Console.WriteLine(test("abc#")); // false
Console.WriteLine(test("abc")); //false
/a(b(cd?)?)?#/
Or for a longer example, to match a prefix of "abcdefg#":
/a(b(c(d(e(fg?)?)?)?)?)?#/
Generating this regex isn't completely trivial, but some options are:
function createPrefixRegex(s) {
// This method creates an unnecessary set of parentheses
// around the last letter, but that won't harm anything.
return new RegExp(s.slice(0,-1).split('').join('(') + ')?'.repeat(s.length - 2) + '#');
}
function createPrefixRegex2(s) {
var r = s[0];
for (var i = 1; i < s.length - 2; ++i) {
r += '(' + s[i];
}
r += s[s.length - 2] + '?' + ')?'.repeat(s.length - 3) + '#';
return new RegExp(r);
}
function createPrefixRegex3(s) {
var recurse = function(i) {
if (i >= s.length - 1) {
return '';
}
if (i === s.length - 2) {
return s[i] + '?';
}
return '(' + s[i] + recurse(i + 1) + ')?';
}
return new RegExp(s[0] + recurse(1) + '#');
}
These may fail if the input string has no prefix before the '#' character, and they assume the last character in the string is '#'.
I have a Scala method that will be given a String like so:
"blah blah sediejdri \"foos\": {\"fizz\": \"buzz\"}, odedrfj49 blah"
And I need to strip the "foos JSON" out of it using pure Java/Scala (no external libs). That is, find the substring matching the pattern:
\"foos\" : {ANYTHING},
...and strip it out, so that the input string is now:
"blah blah sediejdri odedrfj49 blah"
The token to search for will always be \"foos\", but the content inside the JSON curly braces will always be different. My best attempt is:
// Ex: "blah \"foos\": { flim flam }, blah blah" ==> "blah blah blah", etc.
def stripFoosJson(var : toClean : String) : String = {
val regex = ".*\"foos\" {.*},.*"
toClean.replaceAll(regex, "")
}
However I my regex is clearly not correct. Can anyone spot where I'm going awry?
Here are 2 solutions I came up with, hope it helps. I think you forgot to handle possible spaces with \s* etc.
object JsonStrip extends App {
// SOLUTION 1, hard way, handles nested braces also:
def findClosingParen(text: String, openPos: Int): Int = {
var closePos = openPos
var parensCounter = 1 // if (parensCounter == 0) it's a match!
while (parensCounter > 0 && closePos < text.length - 1) {
closePos += 1
val c = text(closePos)
if (c == '{') {
parensCounter += 1
} else if (c == '}') {
parensCounter -= 1
}
}
if (parensCounter == 0) closePos else openPos
}
val str = "blah blah sediejdri \"foos\": {\"fizz\": \"buzz\"}, odedrfj49 blah"
val indexOfFoos = str.indexOf("\"foos\"")
val indexOfFooOpenBrace = str.indexOf('{', indexOfFoos)
val indexOfFooCloseBrace = findClosingParen(str, indexOfFooOpenBrace)
// here you would handle if the brace IS found etc...
val stripped = str.substring(0, indexOfFoos) + str.substring(indexOfFooCloseBrace + 2)
println("WITH BRACE COUNT: " + stripped)
// SOLUTION 2, with regex:
val reg = "\"foos\"\\s*:\\s*\\{(.*)\\}\\s*,\\s*"
println("WITH REGEX: " + str.replaceAll(reg, ""))
}
This regex \\"foos\\": {(.*?)} should match what you want, in most regex engine, you might need to replace " with \". If your JSON can contains other curly brackets, you can use this \\"foos\\": \{(?>[^()]|(?R))*\}, it uses recursion to match balanced groups of brackets. Note that this one only works in pcre regex engine, others won't support recursion.
Using JavaScript & regex I want to split a string on every %20 that is not within quotes, example:
Here%20is%20"a%20statement%20"%20for%20Testing%20"%20The%20Values%20"
//easy to read version: Here is "a statement " for Testing " The Values "
______________ ______________
would return
{"Here","is","a statement ","for","Testing"," The Values "}
but it seems my regex are no longer strong enough to build the expression. Thanks for any help!
A way using the replace method, but without using the replacement result. The idea is to use a closure to fill the result variable at each occurence:
var txt = 'Here%20is%20"a%20statement%20"%20for%20Testing%20"%20The%20Values%20"';
var result = Array();
txt.replace(/%20/g, ' ').replace(/"([^"]+)"|\S+/g, function (m,g1) {
result.push( (g1==undefined)? m : g1); });
console.log(result);
Just try with:
var input = 'Here%20is%20"a%20statement%20"%20for%20Testing%20"%20The%20Values%20"',
tmp = input.replace(/%20/g, ' ').split('"'),
output = []
;
for (var i = 0; i < tmp.length; i++) {
var part = tmp[i].trim();
if (!part) continue;
if (i % 2 == 0) {
output = output.concat(part.split(' '));
} else {
output.push(part);
}
}
Output:
["Here", "is", "a statement", "for", "Testing", "The Values"]
my regex query below does an exact match of a word say Bob or Bill for example
var regExp = new RegExp("^" + inputVal + "$", 'i');
what i want it to do is match anything exactly (Bob or Bill Etc) but not match Fred
so match anything exactly except for Fred, does that make sense?
anyone help me out as to how i do that?
Thanks
EDIT 2:
i thought id show my actual script instead, what im doing is searching a table, and im page load i want to hide rows that contain a string. so if exlucde lenght is greater than 0 hide that row...
function searchPagingTable(inputVal, tablename, fixedsearch, exclude) {
var table = $(tablename);
table.find('tr:not(.header)').each(function (index, row) {
var allCells = $(row).find('td');
if (allCells.length > 0) {
var found = false;
allCells.each(function (index, td) {
if (fixedsearch == 1) {
var regExp = new RegExp("^" + inputVal + "$", 'i');
}
else if (exclude.length > 0)
{
var regExp = new RegExp("^(?!" + exclude + ")", "i");
}
else {
var regExp = new RegExp(inputVal, 'i');
}
if (regExp.test($(td).text())) {
found = true;
return false;
}
});
if (found == true) $(row).show().removeClass('exclude'); else $(row).hide().addClass('exclude');
}
});
pa
ginate();
}
That would be
var exclude = "Fred"
var regExp = new RegExp("^(?!.*" + exclude + ")", "i");
This regex matches any string except those that contain Fred. It doesn't actually match any characters in the string, but that's sufficient if you're just looking for a true/false result.
This will also find strings that contain Alfred or Fredo, so if you don't want that, you need to tell the regex only to look for entire words using word boundaries:
var regExp = new RegExp("^(?!.*\\b" + exclude + "\\b)", "i");
You need to make sure that your exclude string only contains ASCII letters/digits (or underscores) for this to work correctly.
You could populate a list of names you wish to match against:
var validNames = ['bob', 'bill'];
Then lowercase each input and match against the list:
if (validNames.indexOf(inputVal.toLowerCase()) != -1) {
// it's a good name
}
For older browsers you have to shim Array.indexOf()
var re = new RegExp('^\\s*Fred\\s*$','i');
if (inputVal.match(re)) {
// Fred has been found
} else {
// Anything has been found
}
So, for example:
//The string to search through
var str = "This is a string /* with some //stuff in here";
//I'm matching three possible things: "here" or "//" or "/*"
var regEx = new RegExp( "(here)|(\\/\\/)|(\\/\\*)", "g" );
//Loop and find them all
while ( match = regEx.exec( str ) )
{
//Which one is matched? The first parenthesis subexpression? The second?
alert( match[ 0 ] );
}
How do i know I matched the "(//)" instead of the "(here)" without running another regex against the returned match?
You can check which group is defined:
var str = "This is a string /* with some //stuff in here";
var regEx = /(here)|(\/\/)|(\/\*)/g;
while(match = regEx.exec(str)){
var i;
for(i = 1; i < 3; i++){
if(match[i] !== undefined)
break;
}
alert("matched group " + i + ": " + match[i]);
}
Running at http://jsfiddle.net/zLD5V/