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What is the difference between char array and char pointer in C?
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char* and char[] are different types, but it's not immediately apparent in all cases. This is because arrays decay into pointers, meaning that if an expression of type char[] is provided where one of type char* is expected, t...
SQL/mysql - Select distinct/UNIQUE but return all columns?
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You're looking for a group by:
select *
from table
group by field1
Which can occasionally be written with a distinct on statement:
select distinct on field1 *
from table
On most platforms, however, neither of the above will work because the behavior o...
How to convert a std::string to const char* or char*?
How can I convert an std::string to a char* or a const char* ?
8 Answers
8
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Check whether a path is valid
...ts
IEnumerable<string> allMachineDrivers = DriveInfo.GetDrives().Select(drive => drive.Name);
if (!allMachineDrivers.Contains(path.Substring(0, 3))) return false;
// Check if the rest of the path is valid
string InvalidFileNameChars = new string(Path.GetInvalidPathChars());...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
...er=extmail password=extmail
default_pass_scheme = CRYPT
password_query = SELECT username AS user,password AS password FROM mailbox WHERE username = '%u'
user_query = SELECT maildir, uidnumber AS uid, gidnumber AS gid FROM mailbox WHERE username = '%u'
启动dovecot
service dovecot start
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Copying data from one SQLite database to another
...rt Into commands for the tables you want to transfer.
INSERT INTO X.TABLE SELECT * FROM Y.TABLE;
Or, if the columns are not matched up in order:
INSERT INTO X.TABLE(fieldname1, fieldname2) SELECT fieldname1, fieldname2 FROM Y.TABLE;
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Convert int to char in java
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int a = 1;
char b = (char) a;
System.out.println(b);
will print out the char with ascii value 1 (start-of-heading char, which isn't printable).
int a = '1';
char b = (char) a;
System.out.println(b);
will print out the char with asc...
Split List into Sublists with LINQ
...t;> Split<T>(IList<T> source)
{
return source
.Select((x, i) => new { Index = i, Value = x })
.GroupBy(x => x.Index / 3)
.Select(x => x.Select(v => v.Value).ToList())
.ToList();
}
The idea is to first group the elements by indexes. D...
T-SQL: Opposite to string concatenation - how to split string into multiple records [duplicate]
...12))
RETURNS table
AS
RETURN (
WITH Pieces(pn, start, stop) AS (
SELECT 1, 1, CHARINDEX(@sep, @s)
UNION ALL
SELECT pn + 1, stop + 1, CHARINDEX(@sep, @s, stop + 1)
FROM Pieces
WHERE stop > 0
)
SELECT pn,
SUBSTRING(@s, start, CASE WHEN stop > 0 THE...
MYSQL Truncated incorrect DOUBLE value
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Same issue for me. A 'select * from t where id = 6503' worked okay but 'update t set a = "foo" where id = 6503' resulted in ERROR 1292 (22007): Truncated incorrect DOUBLE value: '234805557438#'. id looks like integer but was a varchar. Quoting th...