Boolean values: Difference between revisions
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(→BASIC: changed "QuickBasic" to "Most BASICs") |
(added VB & PB; changed smart quotes to normal quotes under TCL) |
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Everything else is true. The keyword <tt>TRUE</tt> exists. |
Everything else is true. The keyword <tt>TRUE</tt> exists. |
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[http://www.php.net/manual/en/language.types.boolean.php#language.types.boolean.casting] |
[http://www.php.net/manual/en/language.types.boolean.php#language.types.boolean.casting] |
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=={{header|PowerBASIC}}== |
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In addition to what's noted above under [[#BASIC|BASIC]] (above), PowerBASIC for Windows (and probably [[PB/CC]] as well) has the <code>ISTRUE</code> and <code>ISFALSE</code> functions. According to the help file, they "return the logical truth or falsity of a given expression". (PB lacks a boolean data type, so the usual practice is to use integers in [[PB/DOS]] and longs [[PB/CC]] and [[PB/Win]].) |
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<lang powerbasic>DIM x AS LONG |
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x = ISTRUE(1 = 1) ' returns -1 |
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x = ISTRUE(1 = 0) ' returns 0 |
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x = ISFALSE(1 = 1) ' returns 0 |
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x = ISFALSE(1 = 0) ' returns -1</lang> |
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=={{header|PowerShell}}== |
=={{header|PowerShell}}== |
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Test for the boolean value of a string can be stuff like |
Test for the boolean value of a string can be stuff like |
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<lang tcl>if {[string is false -strict $string]} ...</lang> |
<lang tcl>if {[string is false -strict $string]} ...</lang> |
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which will test for |
which will test for "no" or "NO" or "0" or "False" or ... |
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=={{header|TI-89 BASIC}}== |
=={{header|TI-89 BASIC}}== |
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There are boolean literals <code>true</code> and <code>false</code>. No other values may be used where a boolean is expected. |
There are boolean literals <code>true</code> and <code>false</code>. No other values may be used where a boolean is expected. |
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=={{header|Visual Basic}}== |
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VB has the <code>Boolean</code> data type and the constants <code>True</code> and <code>False</code>, in addition to what's listed under [[#BASIC|BASIC]], above. When used outside of a boolean context, <code>True</code> and <code>False</code> return values depending on their context -- <code>-1</code> and <code>0</code> in a numeric context, <code>"True"</code> and <code>"False"</code> if used as strings. |
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<lang visualbasic>Dim x As Boolean |
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x = IIf(Int(Rnd * 2), True, False) |
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MsgBox x</lang> |
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=={{header|XSLT}}== |
=={{header|XSLT}}== |