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How to use the PI constant in C++
... constant.
– Timmmm
Apr 3 '14 at 15:05
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Regular Expression to match only alphabetic characters
I was wondering If I could get a regular expression which will match a string that only has alphabetic characters, and that alone.
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Reasons for using the set.seed function
...: In the academic world, if one claims that his algorithm achieves, say 98.05% performance in one simulation, others need to be able to reproduce it.
?set.seed
Going through the help file of this function, these are some interesting facts:
(1) set.seed() returns NULL, invisible
(2) "Init...
How to efficiently concatenate strings in go
... b.StopTimer()
if s := strings.Repeat("x", b.N); str != s {
b.Errorf("unexpected result; got=%s, want=%s", str, s)
}
}
func BenchmarkBuffer(b *testing.B) {
var buffer bytes.Buffer
for n := 0; n < b.N; n++ {
buffer.WriteString("x")
}
b.StopTimer()
if ...
JOIN two SELECT statement results
...ing it for?
– petrosmm
Apr 18 at 21:05
1
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Combine two data frames by rows (rbind) when they have different sets of columns
...er of dataframes (16) with different column names When I try this I get an error Error: Column ABC can't be converted from character to numeric. Is there a way to convert the columns first?
– sar
Mar 24 at 16:57
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How to obtain the number of CPUs/cores in Linux from the command line?
I have this script, but I do not know how to get the last element in the printout:
27 Answers
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Creating and Update Laravel Eloquent
...fault value or its id column auto incremented one.
Otherwise it will throw error when executing above example:
Illuminate\Database\QueryException with message 'SQLSTATE[HY000]: General error: 1364 Field '...' doesn't have a default value (SQL: insert into `...` (`...`,.., `updated_at`, `created_at`)...
The command rbenv install is missing
...all ruby 2.0.0-p247 using
$ rbenv install 2.0.0-p247
but I received the error message
rbenv: no such command 'install'
All I had to do was to run
$ exec $SHELL -l
and that fixed the problem.
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Converting integer to string in Python
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