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How do I test if a variable is a number in Bash?
... the regex appropriately; for instance:
^[0-9]+([.][0-9]+)?$
...or, to handle numbers with a sign:
^[+-]?[0-9]+([.][0-9]+)?$
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Is there an equivalent of CSS max-width that works in HTML emails?
...n all widely used email clients. I'm wrapping the whole email in a table, and I'd like it to have a width that is up to 98% of the available width, but no greater than 800 pixels. Like this:
<table style="width:98%; max-width:800px;">
...
When is memoization automatic in GHC Haskell?
... in foldl' (+) 0 (y ++ [x])
GHC might notice that y does not depend on x and rewrite the function to
f = let y = [1..30000000] in \x -> foldl' (+) 0 (y ++ [x])
In this case, the new version is much less efficient because it will have to read about 1 GB from memory where y is stored, while th...
Difference between \A \z and ^ $ in Ruby regular expressions
...ending on the regular expression for validation, you always want to use \A and \z. ^ and $ will only match up until a newline character, which means they could use an email like me@example.com\n<script>dangerous_stuff();</script> and still have it validate, since the regex only sees ever...
How to write DataFrame to postgres table?
There is DataFrame.to_sql method, but it works only for mysql, sqlite and oracle databases. I cant pass to this method postgres connection or sqlalchemy engine.
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How do I position one image on top of another in HTML?
... tight in the corner). I am trying to avoid compositing (with ImageMagick and similar) due to performance issues.
10 Answe...
CSS 100% height with padding/margin
With HTML/CSS, how can I make an element that has a width and/or height that is 100% of it's parent element and still has proper padding or margins?
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How to get the nth occurrence in a string?
...n unbounded length input, it needlessly creates an unbounded length array, and then throws most of it away. It would be faster and more efficient just to iteratively use the fromIndex argument to String.indexOf
– Alnitak
Jan 23 '13 at 13:31
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How can I configure NetBeans to insert tabs instead of a bunch of spaces?
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Go to Tools-> Options-> Editor-> Formatting and uncheck Expand tabs to spaces:
Ensure you also pick coherent values for "Number of Spaces per indent" and "Tab Size".
Additionally, you can check all the items in the Language combo and make sure they all use the ge...
How do I get SUM function in MySQL to return '0' if no values are found?
...nformation:
Given three tables (one with all numbers, one with all nulls, and one with a mixture):
SQL Fiddle
MySQL 5.5.32 Schema Setup:
CREATE TABLE foo
(
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
val INT
);
INSERT INTO foo (val) VALUES
(null),(1),(null),(2),(null),(3),(null),(4),(n...