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Lost my schema.rb! Can it be regenerated?
...lright. It simply holds a representation of the structure of your database tables. The data itself is not contained in this file.
To regenerate your schema.rb file, run:
bundle exec rake db:schema:dump
Then simply commit the new schema.rb file and you should be in good shape!
...
Summarizing multiple columns with dplyr? [duplicate]
... 2.87
#> 3 3 2.85 2.95 2.95 3.06
Also don't forget about data.table (use keyby to sort sort groups):
library(data.table)
setDT(df)[, lapply(.SD, mean), keyby = grp]
#> grp a b c d
#> 1: 1 3.079412 2.979412 2.979412 2.914706
#> 2: 2 3.029126 3....
How can I find non-ASCII characters in MySQL?
... but I would suggest trying a variant of a query like this:
SELECT * FROM tableName WHERE columnToCheck NOT REGEXP '[A-Za-z0-9]';
That query will return all rows where columnToCheck contains any non-alphanumeric characters. If you have other characters that are acceptable, add them to the charact...
Static Vs. Dynamic Binding in Java
...e OverridingInternalExample, we can see that compiler generates a constant table where it assigns integer codes to every method call and byte code for the program which I have extracted and included in the program itself (see the comments below every method call)
By looking at above code we can s...
Is it correct to use DIV inside FORM?
...l. You can try it yourself at a HTML validator. Besides, it is almost inevitable these days, since the modern pages are build on div's. If it was not allowed, a simple wrapper or placing the form in a container would already make the page invalid.
– Nrzonline
S...
Remove an entire column from a data.frame in R
... long amount of time and/or fail due to out of memory errors. Package data.table helps address this problem with the := operator:
library(data.table)
> dt <- data.table(a = 1, b = 1, c = 1)
> dt[,a:=NULL]
b c
[1,] 1 1
I should put together a bigger example to show the differences. I...
Switch statement fallthrough in C#?
...ere one takes a value, computes an offset from it (whether by looking up a table indexed by a perfect hash of the value, or by actual arithmetic on the value*). It's worth noting at this point that today, C# compilation will sometimes turn switch into the equivalent if-else, and sometimes use a hash...
MIN/MAX vs ORDER BY and LIMIT
...king at an unindexed field, using MIN() requires a single full pass of the table. Using SORT and LIMIT requires a filesort. If run against a large table, there would likely be a significant difference in percieved performance. As a meaningless data point, MIN() took .36s while SORT and LIMIT took...
Using Panel or PlaceHolder
..., don't get me started with BrowserCaps - it can also become a single cell table in .Net 1.1 on "Downlevel" browsers.
– Zhaph - Ben Duguid
Jan 27 '09 at 13:57
6
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How to vertically align elements in ?
...n, you're not worrying about IE or older browsers.
So you can use display:table-cell and display:table-row like so:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.or...