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How to save a data.frame in R?
...ta.Rda")
Then load it with:
load("data.Rda")
You could also use write.table() or something like that to save the table in plain text, or dput() to obtain R code to reproduce the table.
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What are the most common SQL anti-patterns? [closed]
... will do.
DECLARE @LoopVar int
SET @LoopVar = (SELECT MIN(TheKey) FROM TheTable)
WHILE @LoopVar is not null
BEGIN
-- Do Stuff with current value of @LoopVar
...
--Ok, done, now get the next value
SET @LoopVar = (SELECT MIN(TheKey) FROM TheTable
WHERE @LoopVar < TheKey)
END
Number 3....
UPDATE and REPLACE part of a string
I've got a table with two columns, ID and Value . I want to change a part of some strings in the second column.
9 Answer...
What is the best way to use a HashMap in C++?
...rdered map insert and access is in O(1). It is just another name for a hashtable.
An example with (ordered) std::map:
#include <map>
#include <iostream>
#include <cassert>
int main(int argc, char **argv)
{
std::map<std::string, int> m;
m["hello"] = 23;
// check if ke...
Best way to store password in database [closed]
...gets a hold of your database, they can still use what are known as rainbow tables to be able to "decrypt" the password (at least those that show up in the rainbow table). To get around this, developers add a salt to passwords which, when properly done, makes rainbow attacks simply infeasible to do. ...
How to return result of a SELECT inside a function in PostgreSQL?
...ERY:
CREATE OR REPLACE FUNCTION word_frequency(_max_tokens int)
RETURNS TABLE (txt text -- also visible as OUT parameter inside function
, cnt bigint
, ratio bigint) AS
$func$
BEGIN
RETURN QUERY
SELECT t.txt
, count(*) AS cnt -- co...
Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
I have a sqlite (v3) table with this column definition:
11 Answers
11
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Difference between attr_accessor and attr_accessible
...hat when you create somehow a link between a (Rails) model with a database table, you NEVER, NEVER, NEVER need attr_accessor in your model to create setters and getters in order to be able to modify your table's records.
This is because your model inherits all methods from the ActiveRecord::Base Cl...
How to write the Fibonacci Sequence?
...bject every time the function is called, but normally you wouldn't use a mutable default argument for exactly this reason):
def mem_fib(n, _cache={}):
'''efficiently memoized recursive function, returns a Fibonacci number'''
if n in _cache:
return _cache[n]
elif n > 1:
...
LISTAGG in Oracle to return distinct values
...tagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_column
from the_table
) t
If you need more columns, something like this might be what you are lo...