大约有 22,000 项符合查询结果（耗时：0.0300秒） [XML]
What's the difference between ASCII and Unicode?
...t their language (to support "é", in French, for example). Just using one extra bit doubled the size of the original ASCII table to map up to 256 characters (2^8 = 256 characters). And not 2^7 as before (128).
10000010 -> é (e with acute accent - 130)
10100000 -> á (a with acute accent - 16...
Row count with PDO
...
Using this approach, fetchColumn() returns a string "1234" ... your EDIT has echo count($nRows); - count() is an array function :P. I'd also recommend type casting the result from fetchColumn() to an integer. $count = (int) $stmt->fetchColumn()
–...
Does delete on a pointer to a subclass call the base class destructor?
...n this will happen when the containing object is destroyed.
class A
{
char *someHeapMemory;
public:
A() : someHeapMemory(new char[1000]) {}
~A() { delete[] someHeapMemory; }
};
class B
{
A* APtr;
public:
B() : APtr(new A()) {}
~B() { delete APtr; }
};
class C
{
A Amemb...
Why does Git treat this text file as a binary file?
...ut need of a null (00h) byte for anything other than the nul char (the 'C' string terminator). Thus Git's text definition is that the content (well the first 1k bytes) should not have a null byte when utf-8 encoded. Try stackoverflow.com/questions/2241348/… for a fun read. My original comment ref...
Use '=' or LIKE to compare strings in SQL?
...he (almost religious) discussion, if you should use LIKE or '=' to compare strings in SQL statements.
9 Answers
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Concatenate multiple result rows of one column into one, group by another column [duplicate]
...
Simpler with the aggregate function string_agg() (Postgres 9.0 or later):
SELECT movie, string_agg(actor, ', ') AS actor_list
FROM tbl
GROUP BY 1;
The 1 in GROUP BY 1 is a positional reference and a shortcut for GROUP BY movie in this case.
string_agg() ...
How to use NULL or empty string in SQL
I would like to know how to use NULL and an empty string at the same time in a WHERE clause in SQL Server. I need to find records that have either null values or an empty string. Thanks.
...
install / uninstall APKs programmatically (PackageManager vs Intents)
...ion result notification.
Example code for invoking the uninstall dialog:
String app_pkg_name = "com.example.app";
int UNINSTALL_REQUEST_CODE = 1;
Intent intent = new Intent(Intent.ACTION_UNINSTALL_PACKAGE);
intent.setData(Uri.parse("package:" + app_pkg_name));
intent.putExtra(Intent.EXTRA_RET...
How to index characters in a Golang string?
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Interpreted string literals are character sequences between double quotes "" using the (possibly multi-byte) UTF-8 encoding of individual characters. In UTF-8, ASCII characters are single-byte corresponding to the first 128 Unicode chara...
scala vs java, performance and memory? [closed]
...t occasionally can be annoying. For example, suppose you have an array of strings (called array), and a map from those strings to files (called mapping). Suppose you want to get all files that are in the map and come from strings of length greater than two. In Java, you might
int n = 0;
for (Str...