![]() ![]() #$Matches will be an array where the first element will contain the entire link element #$Matches will contain: WindowsPowerShell Solution for Problem 3 in PowerShell #Note that the double quotes inside the element are escaped using the PowerShell escape symbol $path = "C:\Windows\System32\WindowsPowerShell\" #$Matches will contain: Solution for Problem 2 in PowerShell #No need to escape the backslashes here as they are not the escape symbol Solution for Problem 1 in PowerShell $url = "" In PowerShell a regular expression is enclosed by regular quotation symbols (single or double), however what makes PowerShell different from the other two languages here is that the escape symbol is not the backslash, but instead it is the the apostrophe sign, on US keyboards left of the 1 key directly below the escape key. The second example is relatively typical, as in regular expressions it is expected that you need to escape the escape character if you want to match it. However, as you can see in example three, a benefit of this is that quotation symbols (single or double) do not need to be escaped (just don’t forget about the forward slash in the closing of the link element). In the first case we has a negative side effect of regular expressions being enclosed by forward slashes. The fourth item will contain the text of the link Conclusion for JavaScript The third item will contain the contents of the title attribute The second item will contain the contents on the href attribute The result is an array where the first element will contain the entire link element ![]() Result is WindowsPowerShell Solution for Problem 3 in JavaScript //We need to escape the double quotation symbols as this serves as delimiter for the string. Var path = "C:\\Windows\\System32\\WindowsPowerShell\\" Result is: (group 1 from what is captured) Solution for Problem 2 in JavaScript //We need to escape the backslashes here as this is the escape symbol in JavaScript Solution for Problem 1 in JavaScript var url = "" The symbol used to escape is the backslash, so a regular expressing matching a (one) forward slash in JavaScript would look like this: /\//Īs you may see this can be come complicated quite quickly. ![]() Since this is a common symbol in URLs, it is good to keep this in mind while constructing or copying regexes in JavaScript. However the forward slash itself does need to be escaped. The benefit of this is that Quotation symbols do not need to be escaped. In JavaScript a regex is enclosed in forward slashes like so: /.*/ normal brackets () are used to capture a certain part of the data, in case these are used the result is an array, where the first item is the whole matched part, and then there is an item for each group of brackets.a plus behind a character, dot or square brackets means 1 or more of the proceeding items.an asterisk followed by a question mark *? means zero or more, but this time as few characters as possible.It can be behind a dot, a character or a set of square brackets an asterisk * behind something means zero or more (where it will attempt to get as much as possible).square brackets that start with a ^ match all characters excep the ones inside the square brackets.square brackets match only characters that are inside the square brackets.Matching quotation symbols (getting the href, title and text from A Link).Matching part of a local path (getting WindowsPowerShell from C:\Windows\System32\WindowsPowerShell\).In this post I will go through a few different languages (JavaScript, PowerShell, C#) and for each I will point out a few pitfalls and how to work with them.įor each language we will look at the following situations (problems): Sometimes these characters are also special in the language you are working in. Sometimes you need to match a regex containing special characters. ARGH!! My regex is not working!! It is not matching what it should.
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