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Difference between partition key, composite key and clustering key in Cassandra?
...able stackoverflow_composite (
key_part_one text,
key_part_two int,
data text,
PRIMARY KEY(key_part_one, key_part_two)
);
In a situation of COMPOSITE primary key, the "first part" of the key is called PARTITION KEY (in this example key_part_one is the partition key)...
Why does Popen.communicate() return b'hi\n' instead of 'hi'?
...ing of the bytes you received from the subprocess, you can use decode() to convert them into a printable str:
>>> print(b'hi\n'.decode('ascii'))
hi
Of course, this specific example only works if you actually are receiving ASCII from the subprocess. If it's not ASCII, you'll get an excep...
Make xargs execute the command once for each line of input
...: space.txt: No such file or directory
A better solution is to use tr to convert newlines to null (\0) characters, and then use the xargs -0 argument. Here's an example:
echo "file with space.txt" | tr '\n' '\0' | xargs -0 ls
file with space.txt
If you then need to limit the number of calls yo...
When should I use a struct instead of a class?
...
It logically represents a single value, similar to primitive types
(integer, double, and so on).
It has an instance size smaller than 16 bytes.
It is immutable.
It will not have to be boxed frequently.
share...
What is the difference between instanceof and Class.isAssignableFrom(…)?
...pes. isAssignableFrom() can be used with any class objects:
a instanceof int // syntax error
3 instanceof Foo // syntax error
int.class.isAssignableFrom(int.class) // true
See http://java.sun.com/javase/6/docs/api/java/lang/Class.html#isAssignableFrom(java.lang.Class).
...
Programmatically relaunch/recreate an activity?
...a recreate() method to activities.
I've done that by simply reusing the intent that started the activity. Define an intent starterIntent in your class and assign it in onCreate() using starterIntent = getIntent();. Then when you want to restart the activity, call finish(); startActivity(starterIn...
C# elegant way to check if a property's property is null
... you can use the Null Conditional Operator. So the original test will be:
int? value = objectA?.PropertyA?.PropertyB?.PropertyC;
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Random row from Linq to Sql
...m row in ctx.Customers
where row.IsActive
select row;
int count = qry.Count(); // 1st round-trip
int index = new Random().Next(count);
Customer cust = qry.Skip(index).FirstOrDefault(); // 2nd round-trip
...
Efficient way to remove ALL whitespace from String?
...WhiteSpace1(string input, string expected)
{
string s = null;
for (int i = 0; i < 1000000; i++)
{
s = input.RemoveWhitespace();
}
Assert.AreEqual(expected, s);
}
[Test]
[TestCase("123 123 1adc \n 222", "1231231adc222")]
public void RemoveWhiteSpace2(string input, stri...
Is it possible to figure out the parameter type and return type of a lambda?
...aits<ReturnType(ClassType::*)(Args...) const>
// we specialize for pointers to member function
{
enum { arity = sizeof...(Args) };
// arity is the number of arguments.
typedef ReturnType result_type;
template <size_t i>
struct arg
{
typedef typename std:...