大约有 47,000 项符合查询结果（耗时：0.0487秒） [XML]
Constant Amortized Time
...erations". Amortised time doesn't have to be constant; you can have linear and logarithmic amortised time or whatever else.
Let's take mats' example of a dynamic array, to which you repeatedly add new items. Normally adding an item takes constant time (that is, O(1)). But each time the array is ful...
Finding ALL duplicate rows, including “elements with smaller subscripts”
...gt;% filter(n > 1) # data frame
df %>% add_count(col1, col2) %>% select(n) > 1 # logical vector
For duplicate rows (considering all columns):
df %>% group_by_all %>% add_tally %>% ungroup %>% filter(n > 1)
df %>% group_by_all %>% add_tally %>% ungroup %>% ...
Stop an input field in a form from being submitted
...act with them at all- so if you have a disabled text field, the user can't select the text. If you have a disabled checkbox, the user can't change its state.
You could also write some javascript to fire on form submission to remove the fields you don't want to submit.
...
Xcode 5.1 - No architectures to compile for (ONLY_ACTIVE_ARCH=YES, active arch=x86_64, VALID_ARCHS=i
... @EmilMarashliev just the build target. You'll see it when you select your root project (with blue icon).
– Kjuly
Mar 14 '14 at 17:57
...
Remove Safari/Chrome textinput/textarea glow
... you can interact with. Let accessibility trump aesthetics here.
textarea, select, input, button { outline: none; }
Although, it's been argued that keeping the glow/outline is actually beneficial for accessibility as it can help users see which Element is currently focused.
You can also use the pse...
Javascript / Chrome - How to copy an object from the webkit inspector as code
...
Right-click an object in Chrome's console and select Store as Global Variable from the context menu. It will return something like temp1 as the variable name.
Chrome also has a copy() method, so copy(temp1) in the console should copy that object to your clipboard.
No...
Recover unsaved SQL query scripts
...gled for Retrieve unsaved Scripts and found a solution.
Run the following select script. It provides a list of scripts and its time of execution in the last 24 hours. This will be helpful to retrieve the scripts, if we close our query window in SQL Server management studio without saving the script...
“R cannot be resolved to a variable”? [duplicate]
...test build tools, your project target is set to the earlier one by import. Selecting project build to recent android version availble on you dev env will solve the issue. Ex: For me, by import project build target was being set to Android 4.4.2. This was giving the error. I changed it to Android 5.0...
Best way to give a variable a default value (simulate Perl ||, ||= )
...
return true;
} else {
return false;
}
}
function select_defined(){
$l = func_num_args();
$a = func_get_args();
for ($i=0; $i<$l; $i++){
if ($a[$i]) return $a[$i];
}
}
Examples:
// $foo ||= $bar;
set_unless_defined($foo, $bar);
//$foo = $baz ||...
How to echo shell commands as they are executed
...
You can also toggle this for select lines in your script by wrapping them in set -x and set +x, for example,
#!/bin/bash
...
if [[ ! -e $OUT_FILE ]];
then
echo "grabbing $URL"
set -x
curl --fail --noproxy $SERV -s -S $URL -o $OUT_FILE
set +x...