大约有 43,000 项符合查询结果（耗时：0.0213秒） [XML]
Implicit type conversion rules in C++ operators
...re promoted to int
Note. The minimum size of operations is int. So short/char are promoted to int before the operation is done.
In all your expressions the int is promoted to a float before the operation is performed. The result of the operation is a float.
int + float => float + float = flo...
Get first n characters of a string
How can I get the first n characters of a string in PHP? What's the fastest way to trim a string to a specific number of characters, and append '...' if needed?
...
How do I remove all non alphanumeric characters from a string except dash?
How do I remove all non alphanumeric characters from a string except dash and space characters?
13 Answers
...
NULL values inside NOT IN clause
...
Query A is the same as:
select 'true' where 3 = 1 or 3 = 2 or 3 = 3 or 3 = null
Since 3 = 3 is true, you get a result.
Query B is the same as:
select 'true' where 3 <> 1 and 3 <> 2 and 3 <> null
When ansi_nulls is on, 3 <&...
Count the number occurrences of a character in a string
What's the simplest way to count the number of occurrences of a character in a string?
19 Answers
...
String literals: Where do they go?
... dependent on your platform and could change over time), just use arrays:
char foo[] = "...";
The compiler will arrange for the array to get initialized from the literal and you can modify the array.
share
|
...
Turn a string into a valid filename?
I have a string that I want to use as a filename, so I want to remove all characters that wouldn't be allowed in filenames, using Python.
...
AES Encryption for an NSString on the iPhone
...
@Volomike If i use this, then should i select Export Compliance Information (YES) on iTunes-Connect ?
– Jack
Jul 27 '18 at 6:50
add a comm...
How do I duplicate a whole line in Emacs?
...
which breaks down to
C-a: move cursor to start of line
C-SPACE: begin a selection ("set mark")
C-n: move cursor to next line
M-w: copy region
C-y: paste ("yank")
The aforementioned
C-a C-k C-k C-y C-y
amounts to the same thing (TMTOWTDI)
C-a: move cursor to start of line
C-k: cut ("kill") ...
Base64 length calculation?
...
Each character is used to represent 6 bits (log2(64) = 6).
Therefore 4 chars are used to represent 4 * 6 = 24 bits = 3 bytes.
So you need 4*(n/3) chars to represent n bytes, and this needs to be rounded up to a multiple of 4.
...