How characters are matched in regular expressions

The landlord wants to match $we$223 and $w$3, and the matching formula is as follows:

\w)\$w)

where $ matches "$" and (w) means that it matches any word that includes an underscore of 1 to 3 characters, and since it is a continuous occurrence of $, it can also be rewritten as:

(w)) I tested successfully in VBA in Excel, ** as follows:

sub regs()

dim regex as object

set regex = createobject("")dim s, mat

s = "$we$223adsfjladsjfl$w$3"

(\$w))"

trueset mat =

for each m in mat

msgbox m

nextset regex = nothingend sub

$we\$223

w $3Try to add " in front of the metacharacter as escape.

Character escape. If you want to look up the metacharacter itself, like you look. , or *, and the problem arises:

You can't specify them, because they'll be interpreted as something else. In this case, you have to use the to remove the special meaning of these characters. Therefore, you should use

And*. Of course, to find the itself, you also have to use

For example: wwwunibetter\.com matches c: windows matches c: windows.

Use: +

where " " is an escape character, and because + is a special symbol in the regular representation, it needs to be escaped with " ".

Special characters. 1. + matches the preceding subexpression one or more times. To match the + character, use +

2. Mark the next character as or special character, or original character, or backward reference, or octal escape. For example,'n'Match characters'n'。''Match line breaks.

Sequence'\\'Match"\", while'\('then matched"("。

3、|Indicate a choice between the two items. To match |Use: +

To match the + sign, please add one before the +

+ Plus in front

Regular expression, also known as regular expression, regular expression (often abbreviated as regex, regexp or re) in **, is a concept in computer science. Regular expressions use a single string to describe and match a series of strings that conform to a syntactic rule.

In many texters, regular expressions are often used to retrieve and replace text that fits a certain pattern.

Many programming languages support string manipulation with regular expressions. For example, there is a powerful regex engine built into Perl. The concept of regular expressions was first popularized by tools in UNIX such as SED and GREP.

Regular expressions are usually abbreviated as "regex", and the singular number has regexp, regex, and the plural number has regexps, regexes, regexen.

1. Define a regular expression to test the match of the string is.

2. Next, use the defined regular expression to test the matching result of the word this.

3. Run the program, and you can see that the matching result is true, that is, the regular expression defined above cannot achieve strict matching.

4. If you want to achieve strict matching of regular expressions, you need to add the b symbol to the expression.

5. Run the program, and you can see that the result is false, that is, the regular expression strictly matches the string.

((?=[\x21-\x7e]+)a-za-z0-9])

This one matches all the non-alphabetic and numeric symbols that are visible on the keyboard.

var patrn = /[`~#

/im;if (!

return true;

This is the input box to prevent special characters from not entering verification, including the English and Chinese status of all special characters on the keyboard. Those who need it can choose according to their own needs! Thank you!

[^\w\s]+

Match non-empty, non-alphabetical, non-numeric .

Match English special symbols, including punctuation:

=x21- x7e]+)a-za-z0-9]) There is also a rough way to write (the expansion is very strong haha, you can delete and modify it at will, adapt to your needs):

Use: +where " " " is the escape character.

Because + is a special symbol in regular representations.

So you need to use " " for escaping. Special characters.

Match the preceding subexpression one or more times. To match the + character, use +2, grand to mark the next character as or special character, or literal character, or backward reference, or octal escape. For example,'n'Match characters'n'。

n'Match line breaks.

Sequence'Match", while'then matched"(

Indicate the one-year-old closed choice between the two items. To match |Use: +