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Match multiple cases classes in scala
... matcher(l: Foo): String = {
l match {
case A() => "A"
case B(_) | C(_) => "B"
case _ => "default"
}
}
If you must, must, must extract the parameter and treat them in the same code block, you could:
def matcher(l: Foo): String = {
l match {
case A() => "A"
ca...
Cross-thread operation not valid: Control 'textBox1' accessed from a thread other than the thread it
...se a dispatcher as descibed in the MSDN article:
How to: Make Thread-Safe Calls to Windows Forms Controls
So instead of setting the text property directly in the serialport1_DataReceived method, use this pattern:
delegate void SetTextCallback(string text);
private void SetText(string text)
{
// I...
How are POST and GET variables handled in Python?
... self.response.write(name) # this will write on the document
So you really will have to choose one of those frameworks.
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In Python how should I test if a variable is None, True or False
...
a = 'foo' if a: print 'its true' a is not actually TRUE, it's just not none
– wesm
Apr 3 '15 at 21:06
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Sorting a tab delimited file
...u probably want
sort -k4nr file.txt
to sort file.txt by column 4 numerically in reverse order. (Though the data in the question has even 5 fields so the last field would be index 5.)
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pandas GroupBy columns with NaN (missing) values
...n the Missing Data section of the docs:
NA groups in GroupBy are automatically excluded. This behavior is consistent with R, for example.
One workaround is to use a placeholder before doing the groupby (e.g. -1):
In [11]: df.fillna(-1)
Out[11]:
a b
0 1 4
1 2 -1
2 3 6
In [12]: df.fil...
Can an Option in a Select tag carry multiple values?
...
I was actually wondering this today, and I achieved it by using the php explode function, like this:
HTML Form (in a file I named 'doublevalue.php':
<form name="car_form" method="post" action="doublevalue_action.php">
...
Where is JAVA_HOME on macOS Mojave (10.14) to Lion (10.7)?
...
With the Java optional package or Oracle JDK installed,
adding one of the following lines to your ~/.bash_profile file will set the environment variable accordingly.
export JAVA_HOME="$(/usr/libexec/java_home -v 1.6)"
or
export JAVA_HOME="$(/usr/libexec/java_home -v 1.7)...
Foreign keys in mongo?
...his:
class Student
include Mongoid::Document
field :name
embeds_many :addresses
embeds_many :scores
end
class Address
include Mongoid::Document
field :address
field :city
field :state
field :postalCode
embedded_in :student
end
class Score
include Mongoi...
@UniqueConstraint annotation in Java
...
@Entity
@Table(uniqueConstraints={@UniqueConstraint(columnNames = {"id_1" , "id_2"})})
public class class_name {
@Id
@GeneratedValue
public Long id;
@NotNull
public Long id_1;
@NotNull
public Long id_2;
}
Hope it helped.
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