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What do all of Scala's symbolic operators mean?
...nds
<? <! // Start token for various XML elements
" """ // Strings
' // Indicate symbols and characters
@ // Annotations and variable binding on pattern matching
` // Denote constant or enable arbitrary identifiers
, // Parameter separator
; ...
Kotlin secondary constructor
...1. (solves your case) Define a factory method next to your class
fun C(s: String) = C(s.length)
class C(a: Int) { ... }
usage:
val c1 = C(1) // constructor
val c2 = C("str") // factory method
Technique 2. (may also be useful) Define default values for parameters
class C(name: String? = null) ...
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...
Troubleshooting “Illegal mix of collations” error in mysql
...
This is generally caused by comparing two strings of incompatible collation or by attempting to select data of different collation into a combined column.
The clause COLLATE allows you to specify the collation used in the query.
For example, the following WHERE cla...
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 ...
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...
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...
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...
How do I copy items from list to list without foreach?
...
For a list of elements
List<string> lstTest = new List<string>();
lstTest.Add("test1");
lstTest.Add("test2");
lstTest.Add("test3");
lstTest.Add("test4");
lstTest.Add("test5");
lstTest.Add("test6");
If you want to copy all the elements
List&...
SQLAlchemy: print the actual query
...
In the vast majority of cases, the "stringification" of a SQLAlchemy statement or query is as simple as:
print(str(statement))
This applies both to an ORM Query as well as any select() or other statement.
Note: the following detailed answer is being maintained...