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Dictionaries and default values
...collections import defaultdict
a = defaultdict(lambda: "default", key="some_value")
a["blabla"] => "default"
a["key"] => "some_value"
You can pass any ordinary function instead of lambda:
from collections import defaultdict
def a():
return 4
b = defaultdict(a, key="some_value")
b['absent...
How can I create an object and add attributes to it?
...ant to make a "bunch class", a very simple one already exists in Python -- all functions can have arbitrary attributes (including lambda functions). So, the following works:
obj = someobject
obj.a = lambda: None
setattr(obj.a, 'somefield', 'somevalue')
Whether the loss of clarity compared to the...
Check if a JavaScript string is a URL
...{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
'(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
'(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
'(\\#[-a-z\\d_]*)?$','i'); // fragment locator
return !!pattern.test(str);
}
...
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
... errors.
Here's an example using typical settings for an x86 processor (all used 32 and 64 bit modes):
struct X
{
short s; /* 2 bytes */
/* 2 padding bytes */
int i; /* 4 bytes */
char c; /* 1 byte */
/* 3 padding bytes */
};
struct Y
{
int i; /* 4...
In MySQL, can I copy one row to insert into the same table?
...an existing row in the table) but I want to do this without having to list all the columns after the "select", because this table has too many columns.
...
What does FETCH_HEAD in Git mean?
...it like doing git fetch without arguments (or git remote update), updating all your remote branches, then running git merge origin/<branch>, but using FETCH_HEAD internally instead to refer to whatever single ref was fetched, instead of needing to name things.
...
Get filename and path from URI from mediastore
... cursor.moveToFirst();
return cursor.getString(column_index);
} finally {
if (cursor != null) {
cursor.close();
}
}
}
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f...
Swift - Split string over multiple lines
... some text
over multiple lines
"""
Older versions of Swift don't allow you to have a single literal over multiple lines but you can add literals together over multiple lines:
var text = "This is some text\n"
+ "over multiple lines\n"
...
Cross field validation with Hibernate Validator (JSR 303)
... fields; cross-field validation should be done at the class level. Additionally, the JSR-303 Section 2.2 preferred way to express multiple validations of the same type is via a list of annotations. This allows the error message to be specified per match.
For example, validating a common form:
@F...
How to perform file system scanning
... will not work for release versions of GO in the near future.
There's actually a function in the standard lib just for this: filepath.Walk.
package main
import (
"path/filepath"
"os"
"flag"
)
type visitor int
// THIS CODE NO LONGER WORKS, PLEASE SEE ABOVE
func (v visitor) VisitDir(p...