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Co-variant array conversion from x to y may cause run-time exception
...What it means is this
Control[] controls = new LinkLabel[10]; // compile time legal
controls[0] = new TextBox(); // compile time legal, runtime exception
And in more general terms
string[] array = new string[10];
object[] objs = array; // legal at compile time
objs[0] = new Foo(); // again lega...
How to send an email with Gmail as provider using Python?
...to an SMTP server by telnet and sent EHLO by typo. After I tried HELO many times but the response was different. It took hours to figure out that EHLO is actually a command that SMTP understand and I did the typo.
– Shiplu Mokaddim
Jan 26 '17 at 11:03
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urlencode vs rawurlencode?
...rocess of how to find out this sort of thing on your own in the future any time you want. Bear with me, there'll be a lot of C source code you can skim over (I explain it). If you want to brush up on some C, a good place to start is our SO wiki.
Download the source (or use http://lxr.php.net/ to br...
Computational complexity of Fibonacci Sequence
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You model the time function to calculate Fib(n) as sum of time to calculate Fib(n-1) plus the time to calculate Fib(n-2) plus the time to add them together (O(1)). This is assuming that repeated evaluations of the same Fib(n) take the sam...
What is the worst real-world macros/pre-processor abuse you've ever come across?
...s (myself included) would be a lot more fit if we all did 10 pushups every time a compiler found an error in our code. This might also reduce the occurrence of testing by compilation.
– MikeyB
Jun 25 '09 at 19:52
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What is a CSRF token ? What is its importance and how does it work?
...lude on their own web page when they serve it to you. It is different each time they serve any page to anybody.
The attacker is not able to guess the token, is not able to convince your web browser to surrender it (if the browser works correctly...), and so the attacker will not be able to create a ...
How to get file creation & modification date/times in Python?
... modification date in a cross-platform way is easy - just call os.path.getmtime(path) and you'll get the Unix timestamp of when the file at path was last modified.
Getting file creation dates, on the other hand, is fiddly and platform-dependent, differing even between the three big OSes:
On Windo...
How to check if running in Cygwin, Mac or Linux?
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Sometimes less is more ;) BTW, Wikipedia has a table of example uname output at en.wikipedia.org/wiki/Uname
– schot
Aug 12 '10 at 9:24
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How to filter SQL results in a has-many-through relation
...s thread, with an index where there are two.
I ran all queries a couple of times to populate the cache, then I picked the best of 5 with EXPLAIN ANALYZE.
Relevant indexes (should be the optimum - as long as we lack fore-knowledge which clubs will be queried):
ALTER TABLE student ADD CONSTRAINT stud...
Secondary axis with twinx(): how to add to legend?
...pyplot as plt
from matplotlib import rc
rc('mathtext', default='regular')
time = np.arange(10)
temp = np.random.random(10)*30
Swdown = np.random.random(10)*100-10
Rn = np.random.random(10)*100-10
fig = plt.figure()
ax = fig.add_subplot(111)
lns1 = ax.plot(time, Swdown, '-', label = 'Swdown')
lns2...