大约有 47,000 项符合查询结果（耗时：0.0968秒） [XML]
How to write trycatch in R
...t wrapped insided a function (unlike that
# for the condition handlers for warnings and error below)
},
error=function(cond) {
message(paste("URL does not seem to exist:", url))
message("Here's the original error message:")
message(cond...
How to delete a row by reference in data.table?
...estion. data.table can't delete rows by reference yet.
data.table can add and delete columns by reference since it over-allocates the vector of column pointers, as you know. The plan is to do something similar for rows and allow fast insert and delete. A row delete would use memmove in C to budge u...
Difference: std::runtime_error vs std::exception()
What is the difference between std::runtime_error and std::exception ? What is the appropriate use for each? Why are they different in the first place?
...
Get the position of a div/span tag
... the page. Basically you have to loop up through all the element's parents and add their offsets together.
function getPos(el) {
// yay readability
for (var lx=0, ly=0;
el != null;
lx += el.offsetLeft, ly += el.offsetTop, el = el.offsetParent);
return {x: lx,y: ly};
}
...
Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the La
...blem has been bugging me again.
The simple truth is, atob doesn't really handle UTF8-strings - it's ASCII only.
Also, I wouldn't use bloatware like js-base64.
But webtoolkit does have a small, nice and very maintainable implementation:
/**
*
* Base64 encode / decode
* http://www.webtoolkit.inf...
Can Eclipse refresh resources automatically?
...rces back into sync, the refresh hook only exists for Windows, so on Linux and Mac OS it has to poll the filesystem periodically.
From 3.7 there's a new preference Settings > General > Workspace > Refresh On Access (aka Lightweight Refresh). This preference causes Eclipse to automatically...
Difference between a Structure and a Union
Is there any good example to give the difference between a struct and a union ?
Basically I know that struct uses all the memory of its member and union uses the largest members memory space. Is there any other OS level difference?
...
ping response “Request timed out.” vs “Destination Host unreachable”
...n I ping an IP address, what is the difference between Request timed out and Destination host unreachable returned from the command?
...
lsof survival guide [closed]
lsof is an increadibly powerful command-line utility for unix systems. It lists open files, displaying information about them. And since most everything is a file on unix systems, lsof can give sysadmins a ton of useful diagnostic data.
...
Pro JavaScript programmer interview questions (with answers) [closed]
...ncredible complexity, you should be able to ask relatively basic questions and find out if they are really that good based on their answers. For instance, my standard first question to gauge the rest of the interview is:
In JavaScript, what is the difference between var x = 1 and x = 1? Answer...