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Detecting which UIButton was pressed in a UITableView
...)metaData:(id)target
Enjoy
#import <objc/runtime.h>
static char const * const kMetaDic = "kMetaDic";
#pragma mark - Getters / Setters
- (id)metaData:(id)target {
return objc_getAssociatedObject(target, kMetaDic);
}
- (void)setMetaData:(id)target withObject:(id)newObj {
...
How to un-escape a backslash-escaped string?
...WARNING: value.encode('utf-8').decode('unicode_escape') corrupts non-ASCII characters in the string. Unless the input is guaranteed to only contain ASCII characters, this is not a valid solution.
– Alex Peters
Jun 9 '19 at 11:46
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Signed to unsigned conversion in C - is it always safe?
... need to subtract the given number from max value (256 in case of unsigned char)? For example: 140 when converted to signed number becomes -116. But 20 becomes 20 itself. So any easy trick here?
– Jon Wheelock
Oct 18 '15 at 14:01
...
The static keyword and its various uses in C++
... do different things. For instance, you could put a static void log(const char*) {} in each cpp file, and they could each all log in a different way.
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1052: Column 'id' in field list is ambiguous
...and tbl_section which has both the id field in them. How do I go about selecting the id field, because I always get this error:
...
Left-pad printf with spaces
...
If you want the word "Hello" to print in a column that's 40 characters wide, with spaces padding the left, use the following.
char *ptr = "Hello";
printf("%40s\n", ptr);
That will give you 35 spaces, then the word "Hello". This is how you format stuff when you know how wide you wa...
Is a Java string really immutable?
.... However, looking at the source code of String, we can see that the value character array for a substring is actually copied (using Arrays.copyOfRange(..)). This is why it goes unchanged.
You can install a SecurityManager, to avoid malicious code to do such things. But keep in mind that some libra...
When should I use perror(“…”) and fprintf(stderr, “…”)?
...
perror(const char *s): prints the string you give it followed by a string that describes the current value of errno.
stderr: it's an output stream used to pipe your own error messages to (defaults to the terminal).
Relevant:
char *stre...
Retrieving the last record in each group - MySQL
...x, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY id DESC) AS rn
FROM messages AS m
)
SELECT * FROM ranked_messages WHERE rn = 1;
Below is the original answer I wrote for this question in 2009:
I write the solu...
MySQL ON vs USING?
...n tables ON a column, a set of columns and even a condition. For example:
SELECT * FROM world.City JOIN world.Country ON (City.CountryCode = Country.Code) WHERE ...
USING is useful when both tables share a column of the exact same name on which they join. In this case, one may say:
SELECT ... FR...