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Bash if [ false ] ; returns true
...command always succeeds. To actually run the command, drop the [ command.
if false; then
echo "True"
else
echo "False"
fi
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Logical operators (“and”, “or”) in DOS batch
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You can do and with nested conditions:
if %age% geq 2 (
if %age% leq 12 (
set class=child
)
)
or:
if %age% geq 2 if %age% leq 12 set class=child
You can do or with a separate variable:
set res=F
if %hour% leq 6 set res=T
if %hour% geq 22 set ...
Checking for empty arrays: count vs empty
This question on ' How to tell if a PHP array is empty ' had me thinking of this question
12 Answers
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php 获取操作系统、浏览器版本信息（持续更新） - 更多技术 - 清泛网 - 专...
...ction getOS()
{
$agent = $_SERVER['HTTP_USER_AGENT'];
$os = false;
if (eregi('win', $agent) && strpos($agent, '95')){
$os = 'Windows 95';
}
else if (eregi('win 9x', $agent) && strpos($agent, '4.90')){
$os = 'Windows ME';
}
else if (eregi('win', $agent) && ereg('98', $agent)){
...
boolean in an if statement
...
First off, the facts:
if (booleanValue)
Will satisfy the if statement for any truthy value of booleanValue including true, any non-zero number, any non-empty string value, any object or array reference, etc...
On the other hand:
if (booleanVa...
Is there an easy way to check the .NET Framework version?
The problem is that I need to know if it's version 3.5 SP 1. Environment.Version() only returns 2.0.50727.3053 .
21 Answ...
Check if instance is of a type
Using this to check if c is an instance of TForm .
9 Answers
9
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#if DEBUG vs. Conditional(“DEBUG”)
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It really depends on what you're going for:
#if DEBUG: The code in here won't even reach the IL on release.
[Conditional("DEBUG")]: This code will reach the IL, however calls to the method will be omitted unless DEBUG is set when the caller is compiled.
Personally I u...
How to check if an int is a null
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An int is not null, it may be 0 if not initialized.
If you want an integer to be able to be null, you need to use Integer instead of int.
Integer id;
String name;
public Integer getId() { return id; }
Besides the statement if(person.equals(null)) can't...
When to favor ng-if vs. ng-show/ng-hide?
...at ng-show and ng-hide affect the class set on an element and that ng-if controls whether an element is rendered as part of the DOM.
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