大约有 44,000 项符合查询结果（耗时：0.0638秒） [XML]
C# elegant way to check if a property's property is null
...
could you explain what this does? What is value equal to if PropertyC is null? or if PropertyB is null? what if Object A is null?
– Kolob Canyon
May 18 '19 at 3:04
...
Default argument values in JavaScript functions [duplicate]
...
In javascript you can call a function (even if it has parameters) without parameters.
So you can add default values like this:
function func(a, b){
if (typeof(a)==='undefined') a = 10;
if (typeof(b)==='undefined') b = 20;
//your code
}
and then you can ca...
How can I programmatically get the MAC address of an iphone
... MAC
Somthing I stumbled across a while ago. Originally from here I modified it a bit and cleaned things up.
IPAddress.h
IPAddress.c
And to use it
InitAddresses();
GetIPAddresses();
GetHWAddresses();
int i;
NSString *deviceIP = nil;
for (i=0; i<MAXADDRS; ++i)
{
static unsigned long lo...
Change Placeholder Text using jQuery
...pe=textarea], input[type=password], textarea").each(function(ev)
{
if(!$(this).val()) {
$(this).attr("placeholder", "Type your answer here");
}
});
});
Copy and paste this code in your js file, this will change all placeholder text from whole site.
...
How to check if a variable is null or empty string or all whitespace in JavaScript?
I need to check to see if a variable is null or has all empty spaces or is just blank ("").
12 Answers
...
What is the difference between require() and library()?
What is the difference between require() and library() ?
8 Answers
8
...
How to compare software version number using js? (only number)
...rom the input strings and then compare pairs of parts from the two arrays; if the parts are not equal we know which version is smaller.
There are a few of important details to keep in mind:
How should the parts in each pair be compared? The question wants to compare numerically, but what if we ha...
Why #define TRUE (1==1) in a C boolean macro instead of simply as 1?
... approach will use the actual boolean type (and resolve to true and false) if the compiler supports it. (specifically, C++)
However, it would be better to check whether C++ is in use (via the __cplusplus macro) and actually use true and false.
In a C compiler, this is equivalent to 0 and 1.
(note ...
Why can't R's ifelse statements return vectors?
I've found R's ifelse statements to be pretty handy from time to time. For example:
9 Answers
...
Test if a variable is a list or tuple
In python, what's the best way to test if a variable contains a list or a tuple? (ie. a collection)
13 Answers
...