What are wildcards and regular expressions?

This article shares with you what wildcards and regular expressions have. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

1. Wildcard is the meaning of universal card.

* means to match any character of any length

? Indicates that it matches an arbitrary character

[...] Matches any of the characters listed in parentheses

[!..] Indicates that any of the characters listed in parentheses do not match

two。 Regular expression (regular expression) A string matching pattern standard

2.1. Collection symbol []

[abc] character set (a, b, or z)

[^ abc] negative character set (any character except abc)

2.2. Common metacharacters

^ matches the beginning of the string

The end of the $matching string

\ b match the beginning or end of a word

2.3. Common qualifier {}

{n} repeat n times

{n,} repeat n or more times

{n ~ m} repeat n to m times

2.4. Greed and laziness?

{n,m}? Repeat n to m times, but repeat as little as possible

{n,}? Repeat more than n times, but repeat as little as possible

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