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MySQL ON vs USING?
...d to just say film_id since that would make for an ambiguity:
ERROR 1052 (23000): Column 'film_id' in field list is ambiguous
As for select *, the joining column appears in the result set twice with ON while it appears only once with USING:
mysql> create table t(i int);insert t select 1;c...
Why would adding a method add an ambiguous call, if it wouldn't be involved in the ambiguity
...ms string[]) in its normal form
1: C(params string[]) in its expanded form
2: C<string>(string)
3: C(string, object)
Candidate zero is obviously inapplicable because string is not convertible to string[]. That leaves three.
Of the three, we must determine a unique best method. We do so b...
Is it correct to use JavaScript Array.sort() method for shuffling?
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How to get the input from the Tkinter Text Widget?
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132
To get Tkinter input from the text box, you must add a few more attributes to the normal .get() ...
What is the difference between LL and LR parsing?
...→ T + E
E → T
T → int
Then given the string int + int + int, an LL(2) parser (which uses two tokens of lookahead) would parse the string as follows:
Production Input Action
---------------------------------------------------------
S int + int + int Predi...
How to replace multiple white spaces with one white space
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edited Feb 2 '12 at 23:41
Frank van Puffelen
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Static constant string (class member)
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edited Nov 20 '19 at 15:54
answered Oct 14 '09 at 2:03
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File content into unix variable with newlines
...anscript for a demo:
pax> cat num1.txt ; x=$(cat num1.txt)
line 1
line 2
pax> echo $x ; echo '===' ; echo "$x"
line 1 line 2
===
line 1
line 2
The reason why newlines are replaced with spaces is not entirely to do with the echo command, rather it's a combination of things.
When given a ...
php execute a background process
...Linux machine, I've always handled it like this:
exec(sprintf("%s > %s 2>&1 & echo $! >> %s", $cmd, $outputfile, $pidfile));
This launches the command $cmd, redirects the command output to $outputfile, and writes the process id to $pidfile.
That lets you easily monitor what t...
How to plot two histograms together in R?
...data and combine them.
carrots <- data.frame(length = rnorm(100000, 6, 2))
cukes <- data.frame(length = rnorm(50000, 7, 2.5))
# Now, combine your two dataframes into one.
# First make a new column in each that will be
# a variable to identify where they came from later.
carrots$veg <- ...