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Python: most idiomatic way to convert None to empty string?
... want your function to behave like the str() built-in, but return an empty string when the argument is None, do this:
def xstr(s):
if s is None:
return ''
return str(s)
share
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imp...
What is the difference between canonical name, simple name and class name in Java Class?
...rst.
I did this:
class ClassNameTest {
public static void main(final String... arguments) {
printNamesForClass(
int.class,
"int.class (primitive)");
printNamesForClass(
String.class,
"String.class (ordinary class)");
print...
How exactly does the callstack work?
...teed to cause a crash. This is offset, however, by the fact that a little extra code within each called method will save code at the places where the method is called. For that reason, most of the original Macintosh toolbox routines used the Pascal calling convention.
The C calling convention has...
How to clear MemoryCache?
...
public class SignaledChangeEventArgs : EventArgs
{
public string Name { get; private set; }
public SignaledChangeEventArgs(string name = null) { this.Name = name; }
}
/// <summary>
/// Cache change monitor that allows an app to fire a change notification
...
Convert hyphens to camel case (camelCase)
...
Try this:
var camelCased = myString.replace(/-([a-z])/g, function (g) { return g[1].toUpperCase(); });
The regular expression will match the -i in marker-image and capture only the i. This is then uppercased in the callback function and replaced.
...
Error message 'Unable to load one or more of the requested types. Retrieve the LoaderExceptions prop
...causes the error goes here.
}
catch (ReflectionTypeLoadException ex)
{
StringBuilder sb = new StringBuilder();
foreach (Exception exSub in ex.LoaderExceptions)
{
sb.AppendLine(exSub.Message);
FileNotFoundException exFileNotFound = exSub as FileNotFoundException;
i...
Regular expression for letters, numbers and - _
...will be slightly more complicated.
The above regex also matches the empty string. If you need at least one character, then use + (one-or-more) instead of * (zero-or-more) for repetition.
In any case, you can further clarify your specification (always helps when asking regex question), but hopefull...
Need to understand the usage of SemaphoreSlim
...n (i.e., no FIFO priorities).
When a teacher is around, she "releases" an extra row of 5 footprints on the other side of the corridor such that 5 more kids can play in the room at the same time.
It also has the same "pitfalls" of SemaphoreSlim...
If a kid finishes playing and leaves the room with...
Explicit vs implicit SQL joins
...pe | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------+------+---------------+------+---------+--------------+------+-------+
| 1 | SIMPLE | b | ALL | PRIMARY | NULL | NULL | NULL | 986 | |
| 1 | SIMPLE ...
Deleting all files in a directory with Python
... list of file names which end it '.bak'. The elements of the list are just strings.
Then you could use os.unlink to remove the files. (PS. os.unlink and os.remove are synonyms for the same function.)
#!/usr/bin/env python
import glob
import os
directory='/path/to/dir'
os.chdir(directory)
files=glo...