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Warning message: In `…` : invalid factor level, NA generated
...
Here is a flexible approach, it can be used in all cases, in particular:
to affect only one column, or
the dataframe has been obtained from applying previous operations (e.g. not immediately opening a file, or creating a new data frame).
First, un-factorize a stri...
Is the list of Python reserved words and builtins available in a library?
...break', 'class', 'continue', 'def',
'del', 'elif', 'else', 'except', 'finally', 'for', 'from', 'global', 'if', 'import',
'in', 'is', 'lambda', 'nonlocal', 'not', 'or', 'pass', 'raise', 'return', 'try',
'while', 'with', 'yield']
If you want to include built-in names as well (Python 3), then c...
PL/SQL, how to escape single quote in a string?
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In addition to DCookie's answer above, you can also use chr(39) for a single quote.
I find this particularly useful when I have to create a number of insert/update statements based on a large amount of existing data.
Here's a very quick example:
Lets say we have a very simpl...
multiprocessing: How do I share a dict among multiple processes?
...eates several processes that work on a join-able queue, Q , and may eventually manipulate a global dictionary D to store results. (so each child process may use D to store its result and also see what results the other child processes are producing)
...
Algorithm to get the excel-like column name of a number
...function getNameFromNumber($num) {
$numeric = $num % 26;
$letter = chr(65 + $numeric);
$num2 = intval($num / 26);
if ($num2 > 0) {
return getNameFromNumber($num2 - 1) . $letter;
} else {
return $letter;
}
}
And if you want it one indexed (1 == A, etc):
f...
Convert from ASCII string encoded in Hex to plain ASCII?
...
>>> txt = '7061756c'
>>> ''.join([chr(int(''.join(c), 16)) for c in zip(txt[0::2],txt[1::2])])
'paul'
i'm just having fun, but the important parts are:
>>> int('0a',16) ...
How to use phpexcel to read data and insert into database?
...el_Cell::columnIndexFromString($sheet->getHighestColumn()); I am not infallible `
– Mark Baker
Jun 16 '13 at 21:48
...
“Keep Me Logged In” - the best approach
...e algorithm that you used. For example:
md5(salt+username+ip+salt)
Now, all an attacker needs to do is brute force the "salt" (which isn't really a salt, but more on that later), and he can now generate all the fake tokens he wants with any username for his IP address! But brute-forcing a salt is...
Convert int to ASCII and back in Python
...I to int:
ord('a')
gives 97
And back to a string:
in Python2: str(unichr(97))
in Python3: chr(97)
gives 'a'
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PHP - how to create a newline character?
...eak generated elsewhere (e. g., using double quoted string "\r\n" or using chr function chr(0x0D).chr(0x0A)), the only other way to have a line break within a single quoted string is to literally type it with your editor:
$s = 'some text before the line break
some text after';
Make sure to check ...