大约有 30,000 项符合查询结果（耗时：0.0418秒） [XML]
Logical operators for boolean indexing in Pandas
...l-and since only x or y can be returned. In contrast, x & y triggers x.__and__(y) and the __and__ method can be defined to return anything we like.
– unutbu
Apr 15 '16 at 22:58
...
How do I execute a string containing Python code in Python?
....stderr = codeErr
exec code
# restore stdout and stderr
sys.stdout = sys.__stdout__
sys.stderr = sys.__stderr__
print f(4)
s = codeErr.getvalue()
print "error:\n%s\n" % s
s = codeOut.getvalue()
print "output:\n%s" % s
codeOut.close()
codeErr.close()
...
Is it possible to declare two variables of different types in a for loop?
...:
auto [vec, i32] = std::tuple{std::vector<int>{3, 4, 5}, std::int32_t{12}}
A specific application of this is iterating over a map, getting the key and value,
std::unordered_map<K, V> m = { /*...*/ };
for (auto& [key, value] : m) {
// ...
}
See a live example here
C++14: ...
Getting Django admin url for an object
...written a small filter that I'd use like this: <a href="{{ object|admin_url }}" .... > ... </a>
9 Answers
...
Oracle “(+)” Operator
...e a link at the official Oracle documentation: docs.oracle.com/html/A95915_01/sqopr.htm
– Vargan
Jun 3 '15 at 16:55
...
Starting python debugger automatically on error
...
You can use traceback.print_exc to print the exceptions traceback. Then use sys.exc_info to extract the traceback and finally call pdb.post_mortem with that traceback
import pdb, traceback, sys
def bombs():
a = []
print a[0]
if __name__ == '...
PHP - Get bool to echo false when false
...allows conversion back and forth between boolean and string values." but I tested it out, and (bool)"0" also evaluates to FALSE, so... I dunno. I love PHP, but I can't deny that that's kinda' weird >_>
– Ben
Dec 12 '13 at 23:02
...
How to convert an image to base64 encoding?
...hould be:
$path = 'myfolder/myimage.png';
$type = pathinfo($path, PATHINFO_EXTENSION);
$data = file_get_contents($path);
$base64 = 'data:image/' . $type . ';base64,' . base64_encode($data);
share
|
...
Elegant way to invert a map in Scala
...
Assuming values are unique, this works:
(Map() ++ origMap.map(_.swap))
On Scala 2.8, however, it's easier:
origMap.map(_.swap)
Being able to do that is part of the reason why Scala 2.8 has a new collection library.
...
What is the difference between a field and a property?
...It is private to your class and stores the actual data.
private string _myField;
// this is a property. When accessed it uses the underlying field,
// but only exposes the contract, which will not be affected by the underlying field
public string MyProperty
{
get
...