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How to prevent ifelse() from turning Date objects into numeric objects
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You may use data.table::fifelse (data.table >= 1.12.3) or dplyr::if_else.
data.table::fifelse
Unlike ifelse, fifelse preserves the type and class of the inputs.
library(data.table)
dates <- fifelse(dates == '2011-01-01', dates - 1, d...
How to prepend a string to a column value in MySQL?
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UPDATE tablename SET fieldname = CONCAT("test", fieldname) [WHERE ...]
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SQLite: How do I save the result of a query as a CSV file?
...ex = False)
You can customize the query to only export part of the sqlite table to the CSV file.
You can also run a single command to export all sqlite tables to CSV files:
for table in c.execute("SELECT name FROM sqlite_master WHERE type='table';").fetchall():
t = table[0]
df = pd.read_sql...
How to know when UITableView did scroll to bottom in iPhone
I would like to know when a UITableView did scroll to bottom in order to load and show more content, something like a delegate or something else to let the controller know when the table did scroll to bottom.
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SQL Switch/Case in 'where' clause
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I'd say this is an indicator of a flawed table structure. Perhaps the different location types should be separated in different tables, enabling you to do much richer querying and also avoid having superfluous columns around.
If you're unable to change the structur...
Why is there extra padding at the top of my UITableView with style UITableViewStyleGrouped in iOS7
Starting in iOS7, there is additional space at the top of my UITableView 's which have a style UITableViewStyleGrouped .
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Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
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I had a table that had a circular relationship with others and i was getting the same error. Turns out it is about the foreign key which was not nullable. If key is not nullable related object must be deleted and circular relations d...
Setting element of array from Twig
...That will work only when keys are strings
What I did is recreate another table ( temp) from the initial table (t) and make the keys a string , for example :
{% for key , value in t%}
{% set temp= temp|merge({(key~'_'):value}) %}
{% endfor %}
t keys : 0 , 1 , 2 ..
temp keys : 0_, 1_ , 2_ ......
Is gcc std::unordered_map implementation slow? If so - why?
...red_map, the g++ implementation will automatically rehash to a larger hash table, and this would be a big drag on performance. If I remember correctly, unordered_map defaults to (smallest prime larger than) 100.
I didn't have chrono on my system, so I timed with times().
template <typename TEST...
Ship an application with a database
...re database from there. This is much quicker if the database has a lot of tables and other components. Upgrades are triggered by changing the database version number in the res/values/strings.xml file. Upgrades would then be accomplished by creating a new database externally, replacing the old dat...