共用方式為

Relational Operators

  • 發行項

Relational operators work with all data types and return a Logical value. The following table lists the relational operators.

Relational Operators

Operator Action Code 
<
 Less than 
? 23 < 54
 
>
 Greater than 
? 1 > 2 
=
 Equal to 
? cVar1 = cVar
 
<>, #, !=
 Not equal to 
? .T. <> .F.
 
<=
 Less than or equal to 
? {^1998/02/16} <= {^1998/02/16}
 
>=
 Greater than or equal to 
? 32 >= nHisAge
 
==
 Character string comparison 
? status == "Open"

The == operator can be used when an exact comparison of character strings is needed. If two character expressions are compared with the == operator, the expressions on both sides of the == operator must contain exactly the same characters, including blanks, to be considered equal. The SET EXACT setting is ignored when character strings are compared using ==. See SET EXACT for more information on using the == operator to compare character strings.

You also can use the equal to (=) operator in this version of Visual FoxPro to determine if two object references refer to the same object. The following example demonstrates a simple usage:

CLEAR ALL
X = CREATEOBJECT('Form')
Y = CREATEOBJECT('Form')
? X = Y  && Displays false (.F.)
Z = X
? X = Z  && Displays true (.T.)

See Also

Logical Operators | CREATEOBJECT( ) Function | SET EXACT Command | Operators