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Random row selection in Pandas dataframe
Is there a way to select random rows from a DataFrame in Pandas.
6 Answers
6
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What is a good reason to use SQL views?
...one extra column active.
If your system(s) have gazillion queries that do SELECT whatever FROM T_OLD WHERE whatever, you have two choices for the roll-out:
1) Cold Turkey - Change the DB, and at the same time, change, test and release numerous pieces of code which contained said query. VERY hard t...
Beautiful Soup and extracting a div and its contents by ID
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Beautiful Soup 4 supports most CSS selectors with the .select() method, therefore you can use an id selector such as:
soup.select('#articlebody')
If you need to specify the element's type, you can add a type selector before the id selector:
soup.select('di...
Fragment onCreateView and onActivityCreated called twice
....getFragmentManager().findFragmentByTag(mTag);
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mFragment == null) {
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.replace(android.R.id.content, mFragment, mTag);
} ...
jQuery: Best practice to populate drop down?
...emory (with a string variable) first and then append this string to parent select control should be more efficient, because this will cause only once page layout
– Wint
Jul 2 '15 at 14:41
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MySQL dump by query
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not mysqldump, but mysql cli...
mysql -e "select * from myTable" -u myuser -pxxxxxxxxx mydatabase
you can redirect it out to a file if you want :
mysql -e "select * from myTable" -u myuser -pxxxxxxxx mydatabase > mydumpfile.txt
Update:
Original post asked if...
MySQL get the date n days ago as a timestamp
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DATE_SUB will do part of it depending on what you want
mysql> SELECT DATE_SUB(NOW(), INTERVAL 30 day);
2009-06-07 21:55:09
mysql> SELECT TIMESTAMP(DATE_SUB(NOW(), INTERVAL 30 day));
2009-06-07 21:55:09
mysql> SELECT UNIX_TIMESTAMP(DATE_SUB(NOW(), INTERVAL 30 day));
1244433347
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Using async/await for multiple tasks
...ything but waiting.
int[] ids = new[] { 1, 2, 3, 4, 5 };
Task.WaitAll(ids.Select(i => DoSomething(1, i, blogClient)).ToArray());
On the other hand, the above code with WaitAll also blocks the threads and your threads won't be free to process any other work till the operation ends.
Recommende...
Cause of a process being a deadlock victim
I have a process with a Select which takes a long time to finish, on the order of 5 to 10 minutes. I am currently not using NOLOCK as a hint to the MS SQL database engine. At the same time we have another process doing updates and inserts into the same database and same tables. The first pr...
MySQL: Transactions vs Locking Tables
...ransactions vs locking tables to ensure database integrity and make sure a SELECT and UPDATE remain in sync and no other connection interferes with it. I need to:
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