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Pip install Matplotlib error with virtualenv
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Building Matplotlib requires libpng (and freetype, as well) which isn't a python library, so pip doesn't handle installing it (or freetype).
You'll need to install something along the lines of libpng-devel and freetype-devel (or whatever the equivalent is for...
Is volatile expensive?
...LoadLoad or a LoadStore barrier. Further down the page I see that LoadLoad and LoadStore are effectively no-ops on X86 CPUs. Does this mean that volatile read operations can be done without a explicit cache invalidation on x86, and is as fast as a normal variable read (disregarding the reordering co...
乐高机器人®组件 · App Inventor 2 中文网
... Specifies the bottom of the range used for the BelowRange, WithinRange,
and AboveRange events.
ColorChangedEventEnabled
Specifies whether the ColorChanged event should fire when the DetectColor
property is set to True and the detected color changes
Mode
The current mode of the sensor. On...
How can I list all foreign keys referencing a given table in SQL Server?
...get around this by creating a table, store the result into the table, then select the specific columns. Check out this link for an example :).
– John Odom
Apr 28 '15 at 19:04
3
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ASP.NET MVC How to convert ModelState errors to json
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You can put anything you want to inside the select clause:
var errorList = (from item in ModelState
where item.Value.Errors.Any()
select item.Value.Errors[0].ErrorMessage).ToList();
EDIT: You can extract multiple errors into separate list items by a...
Reshaping data.frame from wide to long format
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Here is another example showing the use of gather from tidyr. You can select the columns to gather either by removing them individually (as I do here), or by including the years you want explicitly.
Note that, to handle the commas (and X's added if check.names = FALSE is not set), I am also us...
Fastest exit strategy for a Panic Button in Crisis/Abuse Websites? [closed]
...on:
it is hard to click on it (you have to be accurate)
it takes time to select it (and a huge amount of time if you are on laptop without a mouse)
it saves you in history
it is accessible via back button / backspace.
And how about the panicking random moves of a woman who is trying to quickly c...
Ruby: How to get the first character of a string
...= "Smith"
first_name = "John"
Then you can get the initials very cleanly and readably:
puts first_name.initial # prints J
puts last_name.initial # prints S
The other method mentioned here doesn't work on Ruby 1.8 (not that you should be using 1.8 anymore anyway!--but when this answer was p...
How to get ID of the last updated row in MySQL?
...)
SET @update_id := 0;
UPDATE some_table SET column_name = 'value', id = (SELECT @update_id := id)
WHERE some_other_column = 'blah' LIMIT 1;
SELECT @update_id;
EDIT by aefxx
This technique can be further expanded to retrieve the ID of every row affected by an update statement:
SET @uids := nul...
How do I generate random number for each row in a TSQL Select?
...mber.
I'd suggest using convert(varbinary,newid()) as the seed argument:
SELECT table_name, 1.0 + floor(14 * RAND(convert(varbinary, newid()))) magic_number
FROM information_schema.tables
newid() is guaranteed to return a different value each time it's called, even within the same batch, so usi...