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Switching between GCC and Clang/LLVM using CMake
...sudo update-alternatives --config c++
Will print something like this:
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/g++ 20 auto mode
1 /usr/bin/clang++ 10 manual mode
2 ...
Array or List in Java. Which is faster?
...;std::string>, although copying by value without a pointer as such, the character arrays will form an object for string (and these will not usually be shared).
If this particular code is really performance-sensitive, you could create a single char[] array (or even byte[]) for all the characters ...
What is the difference between a “function” and a “procedure”?
... a Procedure, whereas in a Function we can't.
In SQL:
A Procedure allows SELECT as well as DML (INSERT, UPDATE, DELETE) statements in it, whereas Function allows only SELECT statement in it.
Procedures can not be utilized in a SELECT statement, whereas Functions can be embedded in a SELECT stateme...
MySQL convert date string to Unix timestamp
...
Here's an example of how to convert DATETIME to UNIX timestamp:
SELECT UNIX_TIMESTAMP(STR_TO_DATE('Apr 15 2012 12:00AM', '%M %d %Y %h:%i%p'))
Here's an example of how to change date format:
SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(STR_TO_DATE('Apr 15 2012 12:00AM', '%M %d %Y %h:%i%p')),'%m-%d-...
How to delete a row by reference in data.table?
...el.idxs' vs. 'keep.idxs'
keep.idxs <- setdiff(DT[, .I], del.idxs); # select row indexes to keep
cols = names(DT);
DT.subset <- data.table(DT[[1]][keep.idxs]); # this is the subsetted table
setnames(DT.subset, cols[1]);
for (col in cols[2:length(cols)]) {
DT.subset[, (col) := DT[...
Repeat each row of data.frame the number of times specified in a column
...es
library(dplyr)
df %>%
slice(rep(seq_len(n()), freq)) %>%
select(-freq)
# var1 var2
#1 a d
#2 b e
#3 b e
#4 c f
#5 c f
#6 c f
seq_len(n()) part can be replaced with any of the following.
df %>% slice(rep(1:nrow(df), freq)) %>% select(-...
What is the difference between onBlur and onChange attribute in HTML?
...
An example to make things concrete. If you have a selection thus:
<select onchange="" onblur="">
<option>....
</select>
the onblur() is called when you navigate away. The onchange() is called when you select a different option from the selection - i.e....
How to read if a checkbox is checked in PHP?
...
checkboxes as an array and foreach ($_POST['food'] as $selected_food) to work on checked one is nice, thanks
– bcag2
May 4 at 13:02
add a comment
...
Where to place the 'assets' folder in Android Studio?
...
Select the app folder and then:
File > New > folder > assets Folder ,
the default location is inside /main folder
share
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...
Reading/writing an INI file
...bly.GetExecutingAssembly().GetName().Name;
[DllImport("kernel32", CharSet = CharSet.Unicode)]
static extern long WritePrivateProfileString(string Section, string Key, string Value, string FilePath);
[DllImport("kernel32", CharSet = CharSet.Unicode)]
static extern in...