Regular Expressions 101

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/
^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[#$%/()=¿?*+-])(?=(?:([\w\d])\1?(?!\1\1)))(?!(?=.*(palabra1|palabra2|palabraN))).{8,20}$
/
^ asserts position at start of the string
Positive Lookahead
(?=.*\d)
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\d matches a digit (equivalent to [0-9])
Positive Lookahead
(?=.*[a-z])
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[a-z]
a-z matches a single character in the range between a (index 97) and z (index 122) (case sensitive)
Positive Lookahead
(?=.*[A-Z])
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[A-Z]
A-Z matches a single character in the range between A (index 65) and Z (index 90) (case sensitive)
Positive Lookahead
(?=.*[#$%/()=¿?*+-])
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Match a single character present in the list below
[#$%/()=¿?*+-]
#$%/()=¿?*+
matches a single character in the list #$%/()=¿?*+ (case sensitive)
- matches the character - with index 4510 (2D16 or 558) literally (case sensitive)
This hyphen is treated literally, which might be confusing for others. Consider escaping it or placing at the start or end of the class!
Positive Lookahead
(?=(?:([\w\d])\1?(?!\1\1)))
Assert that the Regex below matches
Non-capturing group
(?:([\w\d])\1?(?!\1\1))
1st Capturing Group
([\w\d])
Match a single character present in the list below
[\w\d]
\w matches any word character (equivalent to [a-zA-Z0-9_])
\d matches a digit (equivalent to [0-9])
\1
matches the same text as most recently matched by the 1st capturing group
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
Negative Lookahead
(?!\1\1)
Assert that the Regex below does not match
\1 matches the same text as most recently matched by the 1st capturing group
\1 matches the same text as most recently matched by the 1st capturing group
Negative Lookahead
(?!(?=.*(palabra1|palabra2|palabraN)))
Assert that the Regex below does not match
Positive Lookahead
(?=.*(palabra1|palabra2|palabraN))
Assert that the Regex below matches
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Capturing Group
(palabra1|palabra2|palabraN)
1st Alternative
palabra1
palabra1
matches the characters palabra1 literally (case sensitive)
2nd Alternative
palabra2
palabra2
matches the characters palabra2 literally (case sensitive)
3rd Alternative
palabraN
palabraN
matches the characters palabraN literally (case sensitive)
.
matches any character (except for line terminators)
{8,20} matches the previous token between 8 and 20 times, as many times as possible, giving back as needed (greedy)
$ asserts position at the end of the string
Your regular expression does not match the subject string.

Regular Expression
No Match

/
/

Test String

Substitution

Processing...