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&& (AND) and || (OR) in IF statements
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No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write:
if (str != null && !str.isEmpty()) {
doSomethingWith(str.charAt(0));
}
or, the other way around
if ...
Which terminal command to get just IP address and nothing else?
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It says that -i and -I are both illegal options
– Mason
Dec 16 '11 at 3:08
3
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Multiple queries executed in java in single statement
...c.. Acceptable values for allowMultiQueries property are true, false, yes, and no. Any other value is rejected at runtime with an SQLException.
String dbUrl = "jdbc:mysql:///test?allowMultiQueries=true";
Unless such instruction is passed, an SQLException is thrown.
You have to use execute( S...
How do I calculate the normal vector of a line segment?
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if we define dx=x2-x1 and dy=y2-y1, then the normals are (-dy, dx) and (dy, -dx).
Note that no division is required, and so you're not risking dividing by zero.
share
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Counting the number of True Booleans in a Python List
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That is not idiomatic and makes "abuse" of the type coercion of bool.
– Jan Segre
Sep 4 '14 at 22:19
26
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Bash if [ false ] ; returns true
Been learning bash this week and ran into a snag.
6 Answers
6
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Using comparison operators in Scala's pattern matching system
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You can add a guard, i.e. an if and a boolean expression after the pattern:
a match {
case 10 => println("ten")
case x if x > 10 => println("greater than ten")
case _ => println("less than ten")
}
Edit: Note that this is more than...
Google Maps: how to get country, state/province/region, city given a lat/long value?
...e. I need to store this information in a manner that hierarchy is preserve and without duplicates (e.g. "USA" and "United States" and "United States of America" are the same country; I only want one instance of this country in my database).
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Remove trailing zeros
....ToString("G29")
This should work for all input.
Update Check out the Standard Numeric Formats I've had to explicitly set the precision specifier to 29 as the docs clearly state:
However, if the number is a Decimal and the precision specifier is omitted, fixed-point notation is always used an...
Dashed line border around UIView
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You can set the border with this pattern using Layer and Bezier path like below examples.
Objective-C
CAShapeLayer *yourViewBorder = [CAShapeLayer layer];
yourViewBorder.strokeColor = [UIColor blackColor].CGColor;
yourViewBorder.fillColor = nil;
yourViewBorder.lineDashPattern...