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Filter dataframe rows if value in column is in a set list of values [duplicate]
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@dbyte: You just use the ~ operator: rpt[~rpt['STK_ID'].isin(stk_list)]
– BrenBarn
Jun 26 '13 at 17:43
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How to get last N records with activerecord?
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Updated Answer (2020)
You can get last N records simply by using last method:
Record.last(N)
Example:
User.last(5)
Returns 5 users in descending order by their id.
Deprecated (Old Answer)
An active record query like this I think would get you what you want ('Something' is the mode...
find() with nil when there are no records
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Yes, just do:
Challenge.find_by_id(10)
For Rails 4 and 5:
Challenge.find_by(id: 10)
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How do I change an HTML selected option using JavaScript?
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Change
document.getElementById('personlist').getElementsByTagName('option')[11].selected = 'selected'
to
document.getElementById('personlist').value=Person_ID;
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selecting unique values from a column
... DISTINCT operator in MySQL:
SELECT DISTINCT(Date) AS Date FROM buy ORDER BY Date DESC;
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jQuery selector regular expressions
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The regex selector by @padolsey works great. Here's an example where you can iterate over text, file and checkbox input fields or textareas with it: $j('input:regex(type, text|file|checkbox),textarea').each(function(index){ // ... });
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App Inventor 2 CustomWebView 拓展：高级版Web浏览器，完美浏览现代Web前...
...umberOfMatches’ and ‘isDoneCounting’
GotCertificate(isSecure,issuedBy,issuedTo,validTill)
Event raised after getting SSL certificate of current displayed url/website with boolean ‘isSecure’ and Strings ‘issuedBy’,’issuedTo’ and ‘validTill’.If ‘isSecure’ is false and oth...
How do I get the last inserted ID of a MySQL table in PHP?
...n the server on a per-connection basis. This means that the value returned by the function to a given client is the first AUTO_INCREMENT value generated for most recent statement affecting an AUTO_INCREMENT column by that client. This is the reason you should not use select MAX(ID)
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How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL?
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(SELECT home, MAX(datetime) AS MaxDateTime
FROM topten
GROUP BY home) groupedtt
ON tt.home = groupedtt.home
AND tt.datetime = groupedtt.MaxDateTime
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Can I concatenate multiple MySQL rows into one field?
...person_id, GROUP_CONCAT(hobbies SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Ludwig stated in his comment, you can add the DISTINCT operator to avoid duplicates:
SELECT person_id, GROUP_CONCAT(DISTINCT hobbies SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Jan stated i...