Signs in regular expressions

Description

* (star)

sign(s) left to the star can appear in any number or not at all

+ (plus)

sign(s) left to the plus can appear in any number but at least one time

? (question mark)

sign(s) left of the question mark can appear one time or not at all.

. (dot)

the dot replaces any sign which appears one time

[^] (cap with brackets)

signs within the brackets and behind the cap are excluded

^ (cap without brackets)

signs behind the cap are to position at the beginning of a string

$ (dollar sign)

signs followed by a Dollar sign are to position at the end of a string.

Possible regular expressions :

a prefixed backslash nullifies the function of all other signs in a regular expression

Expression

Description

Example

XYZ

Reads out X and Z as well as the defined expression between X and Z.

ABC XYZ DEF

X . Z

Reads out X and Z as well as any expression between X and Z.

ABC XAZ DEF

ABC XeZ DEF

ABC X4Z DEF

etc.

X .* Z

Reads out X and Z as well as any expression (in any number) or no sign between X and Z.

ABC XZ DEF

ABC XAZ DEF

ABC XApZ DEF

etc.

X .+ Z

Reads out X and Z as well as any expression (in any number but at least one time) between X and Z.

ABC XAZ DEF

ABC XrGZ DEF

etc.

X .? Z

Reads out X and Z as well as one or no expression between X and Z.

ABC XZ DEF

ABC XAZ DEF

ABC X8Z DEF

etc.

XA + Z

Selects X and Z as well as A (in any number but at least one time) between X and Z.

ABC XAZ DEF

ABC XAAZ DEF

ABC XAAAZ DEF

etc.

XA ? Z

Reads out X and Z as well as one A or no A between X and Z.

ABC XZ DEF

ABC XAZ DEF

X[AB] * Z

Reads out X and Z as well as any combination between A and B or no expression between X and Z.

ABC XZ DEF

ABC XAZ DEF

ABC XBZ DEF

ABC XABZ DEF

ABC XBAZ DEF

ABC XAAZ DEF

ABC XBBZ DEF

ABC XABAZ DEF

ABC XBBAABAZ DEF

etc.

X[ ^ AB]Z

Reads out X and Z as well as any combination between X and Z, apart from A and B.

ABC X AB Z DEF

Expression

Description

Example

X[A-C]Z

Reads out X and Z as well as A, B or C between X and Z.

ABC XAZ DEF

ABC XBZ DEF

ABC XCZ DEF

X[0-9] * Z

Reads out X and Z as well as any combination of numbers or no expression between X and Z.

ABC XZ DEF

ABC X0Z DEF

ABC X1Z DEF

ABC X6372Z DEF

etc.

X[A-Z][a-z] * Z

Reads out X and Z as well as string starting with capital letter and continuing with lower case (in any number) or no String between X and Z.

ABC XZ DEF

ABC XAZ DEF

ABC XAaZ DEF

ABC XAgsagZ DEF

ABC XBZ DEF

etc.

^ ABC

Reads out a defined expression if it is positioned at the beginning of the string.

ABC XYZDEF

Not with:

XABCZDEF

ABC $

Reads out a defined expression if it is positioned at the end of the string.

XYZDEF ABC

Not with:

ABCXYZDEF

X \. Z

Nullifies the function of the dot within the regular expression, so a dot (also $, ^, \, etc.) can be read out of a string, too.

ABCX . ZDEF