Agilent Technologies FS2010 Guide de l'utilisateur télécharger pdf (Page 49)

Programming with VISA 3

Agilent VISA User’s Guide 49

grouping operator, and the or operator | in a regular

expression has the lowest precedence. The following table

provides detailed descriptions of special characters and

operators. Some example expressions follow in Table 14.

Table 13 Descriptions of Special Characters and Operators

Special

Characters and

Operators

Description

? Matches any one character.

\ Makes the character that follows it an ordinary character

instead of special character. For example, when a question

mark follows a backslash (e.g.,’ '\?’), it matches the '?'

character instead of any one character.

[list] Matches any one character from the enclosed list. A hyphen

can be used to match a range of characters.

[^list] Matches any character not in the enclosed list. A hyphen

can be used to match a range of characters.

* Matches 0 or more occurrences of the preceding character

or expression.

+ Matches 1 or more occurrences of the preceding character

or expression.

exp|exp Matches either the preceding or following expression. The

or operator | matches the entire expression that precedes

or follows it and not just the character that precedes or

follows it. For example, VXI|GPIB means (VXI) | (GPIB),

not VXI(I|G)PIB.

(exp) Grouping characters or expressions.

“ “ Sends a blank space.

\n Sends the ASCII line feed character. The END identifier will

also be sent.

\r Sends an ASCII carriage return character.

\t Sends an ASCII TAB character.

\### Sends ASCII character specified by octal value.

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Agilent Technologies FS2010 Guide de l'utilisateur Page 49