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Finding row index containing maximum value using R
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See ?order. You just need the last index (or first, in decreasing order), so this should do the trick:
order(matrix[,2],decreasing=T)[1]
share
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My Understanding of HTTP Polling, Long Polling, HTTP Streaming and WebSockets
..., long poll, streaming.
Bi-direcitonal: WebSockets, plugin networking
In order of increasing latency (approximate):
WebSockets
Plugin networking
HTTP streaming
HTTP long-poll
HTTP polling
CORS (cross-origin support):
WebSockets: yes
Plugin networking: Flash via policy request (not sure about...
Hashing a dictionary?
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@Ceaser That won't work because tuple implies ordering but dict items are unordered. frozenset is better.
– Antimony
Jul 30 '12 at 11:55
28
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MySQL INNER JOIN select only one row from second table
... = (
SELECT id
FROM payments AS p2
WHERE p2.user_id = u.id
ORDER BY date DESC
LIMIT 1
)
Or
SELECT u.*, p.*
FROM users AS u
INNER JOIN payments AS p ON p.user_id = u.id
WHERE NOT EXISTS (
SELECT 1
FROM payments AS p2
WHERE
p2.user_id = p.user_id AND
(p...
Can you do greater than comparison on a date in a Rails 3 search?
...er.id, :notetype => p[:note_type]).
where("date > ?", p[:date]).
order('date ASC, created_at ASC')
or you can also convert everything into the SQL notation
Note.
where("user_id = ? AND notetype = ? AND date > ?", current_user.id, p[:note_type], p[:date]).
order('date ASC, created...
What are the most common SQL anti-patterns? [closed]
...t *, you get whatever is in the table. Those columns may change names and order. Client code frequently relies on names and order. Every 6 months I'm asked how to preserve column order when modifying a table. If the rule was followed it wouldn't matter.
– Amy B
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Cookies vs. sessions
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Short answer
Rules ordered by priority:
Rule 1. Never trust user input : cookies are not safe. Use sessions for sensitive data.
Rule 2. If persistent data must remain when the user closes the browser, use cookies.
Rule 3. If persistent data d...
Meaning of tilde in Linux bash (not home directory)
...tion is usually controlled by NSS; so by default values are pulled out of /etc/passwd, though it can be configured to retrieve the information using any source desired, such as NIS, LDAP or an SQL database.
Tilde expansion is more than home directory lookup. Here's a summary:
~ $HOME
~f...
Getting error: Peer authentication failed for user “postgres”, when trying to get pgsql working with
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The problem is still your pg_hba.conf file (/etc/postgresql/9.1/main/pg_hba.conf*).
This line:
local all postgres peer
Should be:
local all postgres md5
* If you can't fin...
In which order do CSS stylesheets override?
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Then there's no specific rule as to in what order stylesheets load? I understand how CSS displays in terms of specificity, but then I'll assume my master sheet will load unless overridden.
– ian5v
Feb 27 '12 at 1:49
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