what is the meaning of meta character?

Answer 1

A special character in a program that provides info about other characters

Answer 2

A metacharacter is a character in a regular expression that either a) represents one or more other characters in an expression, or b) modifies the expression in some way.

For example, if the raw string r"gr.y" is used as a regular expression, the "." is a metacharacter. It doesn't mean only a literal dot, but rather stands for "any single non-newline character". So that expression can match "gray", "grey", "grXy", and yes, even "gr.y" - because a dot which is in a plain string (ie - one that is not being used as a regular expression) is, after all, also a non-newline character.

If we use the raw string r"s.*m" as a regular expression, there are two metacharacters: ".", and "*". The "." still stands for "one non-newline character", but the "*" means "zero or more of the preceding thing". In this case, the "preceding thing" happens to be ".", so putting the two together means "zero or more non-newline characters". So that regex matches "spam", "system", "stadium", and also "sm" (because ".*" matches zero characters too).

Hope that clarifies it for you, but feel free to ask for clarification. :-)

Answer 3

Often things like: Special. Placeholder. Representative/Symbolic. Modifier.

They're often used for portability (write once, works everywhere).

For example:

\t is a metacharacter for Tab (ASCII 009). It's easier than figuring out how to 'send a tab' sometimes (like in bash, which steals the tab: to insert one you'd have to press Ctrl-V then Tab; who wants to always do that?)

\n is newline - it's 1 character on Linux and 2 characters on Windows. If you didn't use the metacharacter you'd have to write code at least twice, detect the OS, accommodate files from other systems....it's messy.

It also helps you read code, like in regular expressions, or protects the interface: many characters represented in a 'meta' way aren't printable or would cause bizarre behavior in the console.

Answer 4

Metacharacters make regular expressions more powerful than normal string methods.

Answer 5

Ema, how did you get a lot of xp on html?

Answer 6

It is special type of character which manipulates the another character of the program.

Like n change to newline command if we use meta character before it " \n "
So on like *, [ ] etc,