Mikroelektronika MIKROE-742 데이터 시트

^

- matches string 

' 

PORTA '

only if it's at the beginning of line 

- matches string 

' 

PORTA ' 

only if it's at the end of line 

^

- matches string 

' 

PORTA '

only if it's the only string in line 

- matches strings like 

'

PORTA', 'PORTB', 'PORT1'

and so on 

The 

"^"

metacharacter by default is only guaranteed to match beginning of the input

string/text, and the 

"

$"

metacharacter only at the end. Embedded line separators

will not be matched by

^"

or 

"

$"

. 

You may, however, wish to treat a string as a multi-line buffer, such that the 

"^"

will match

after any line separator within the string, and 

"

$"

will match before any line separator. 

Regular expressions works with line separators as recommended at 
http://www.unicode.org/unicode/reports/tr18/ 

- an alphanumeric character (including 

"_"

) 

- a nonalphanumeric character 

- a numeric character 

- a non-numeric character 

- any space (same as [

) 

- a non space 

You may use 

\w, \d

and 

within custom character classes.

- matches strings like

and so on, but not 

'

routine'

,

'

routime'

and so on. 

A word boundary (

"

\b"

) is a spot between two characters that has an alphanumeric char-

acter (

"\w"

) on one side, and a nonalphanumeric character (

"

\W"

) on the other side (in

either order), counting the imaginary characters off the beginning and end of the string as
matching a 

"

\W"

. 

- match a word boundary) 

- match a non-(word boundary) 

69

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 2