大约有 22,000 项符合查询结果（耗时：0.0293秒） [XML]
SQL/mysql - Select distinct/UNIQUE but return all columns?
...y applicable to numeric values, but also compare the alphabetical order of string values.
SELECT country, MAX(city) FROM locations
GROUP BY country
will result in:
--country-- --city--
France Paris
Poland Krakow
Italy Milano
or:
SELECT country, MIN(city) FROM locations
GROU...
Return Boolean Value on SQL Select Statement
...
This returns a string, not a boolean
– OMG Ponies
Apr 30 '12 at 2:24
...
Wget output document and headers to STDOUT
...
Try the following, no extra headers
wget -qO- www.google.com
Note the trailing -. This is part of the normal command argument for -O to cat out to a file, but since we don't use > to direct to a file, it goes out to the shell. You can use -q...
How do I show a console output/window in a forms application?
...application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// initialize console handles
InitConsoleHandles();
if (args.Length != 0)
{
if (args[0].Equals("waitfordebugger"))
{
MessageBox.Sh...
Round to at most 2 decimal places (only if necessary)
... drops any "extra" zeroes at the end.
// It changes the result (which is a string) into a number again (think "0 + foo"),
// which means that it uses only as many digits as necessary.
It seems like Math.round is a better solution. But it is not! In some cases it will NOT round correctly:
Math.round...
What's the scope of the “using” declaration in C++?
I'm using the 'using' declaration in C++ to add std::string and std::vector to the local namespace (to save typing unnecessary 'std::'s).
...
What are the differences between SML and OCaml? [closed]
...a top-level primitive in SML; it's not part of the Caml library. The Caml string library doesn't provide a fold function (at least not as of version 3.08). Implementations of many of the Caml List functions are unsafe for very long lists; they blow the stack.
The type systems are subtly different:...
map function for objects (instead of arrays)
...
There is no need to add an extra HTTP call and an extra library just for one function. In any case, this answer is now outdated and you can simply call Object.entries({a: 1, b: 2, c: 3}) to get an array.
– user6269864
...
What's the difference between the various methods to get a Context?
...e:
public class MyApplication extends Application {
public static String getPackageName() {
String packageName = null;
try {
PackageInfo mPackageInfo = getApplicationContext().getPackageManager().getPackageInfo(getApplicationContext().getPackageName(), 0);
...
Split (explode) pandas dataframe string entry to separate rows
I have a pandas dataframe in which one column of text strings contains comma-separated values. I want to split each CSV field and create a new row per entry (assume that CSV are clean and need only be split on ','). For example, a should become b :
...