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Difference between staticmethod and classmethod
... code will help: Notice the difference in the call signatures of foo, class_foo and static_foo:
class A(object):
def foo(self, x):
print "executing foo(%s, %s)" % (self, x)
@classmethod
def class_foo(cls, x):
print "executing class_foo(%s, %s)" % (cls, x)
@staticme...
When should you use constexpr capability in C++11?
...lues over and over?
int func (int n) {
static std::map<int, int> _cached;
if (_cached.find (n) == _cached.end ())
_cached[n] = n > 0 ? n + func (n-1) : n;
return _cached[n];
}
The result
By introducing your silly optimization, you just broke every usage of your function th...
What is the most efficient way to store a list in the Django models?
...
See docs.djangoproject.com/en/3.0/topics/db/examples/many_to_one
– Jon Ison
Jul 2 at 9:42
...
Learning Python from Ruby; Differences and Similarities
...at to the collection each method (if list supported this method):
def some_operation(value):
...
collection.each(some_operation)
That doesn't flow very nicely. So, typically the following non-functional approach would be used in Python:
for value in collection:
...
Using resources in a sa...
How do I check if a string is a number (float)?
...
It's not provided 'out of the box' because if is_number(s): x = float(x) else: // fail is the same number of lines of code as the try: x = float(x) catch TypeError: # fail. This utility function is an entirely unecessary abstraction.
– ovangle
...
Drop all tables whose names begin with a certain string
...RE @cmd varchar(4000)
DECLARE cmds CURSOR FOR
SELECT 'drop table [' + Table_Name + ']'
FROM INFORMATION_SCHEMA.TABLES
WHERE Table_Name LIKE 'prefix%'
OPEN cmds
WHILE 1 = 1
BEGIN
FETCH cmds INTO @cmd
IF @@fetch_status != 0 BREAK
EXEC(@cmd)
END
CLOSE cmds;
DEALLOCATE cmds
This is cleane...
Group by multiple columns in dplyr, using string vector input
...
Since this question was posted, dplyr added scoped versions of group_by (documentation here). This lets you use the same functions you would use with select, like so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = s...
How do I join two lines in vi?
...ou join lines as is -- without adding or removing whitespaces:
S<Switch_ID>_F<File type>
_ID<ID number>_T<date+time>_O<Original File name>.DAT
Result:
S<Switch_ID>_F<File type>_ID<ID number>_T<date+time>_O<Original File name>.DAT
With...
How to change the Eclipse default workspace?
...
On ubuntu I went to ~/.eclipse/org.eclipse.platform_4.3.0_1473617060_linux_gtk_x86_64/configuration/config.ini and added this line osgi.instance.area.default=@user.home/workspace pointing it to where ever i wanted.
– Jerinaw
Feb 7 '14 at...
How to send an email with Gmail as provider using Python?
... line and use CRLF as EOL markers.
E.g.
msg = "\r\n".join([
"From: user_me@gmail.com",
"To: user_you@gmail.com",
"Subject: Just a message",
"",
"Why, oh why"
])
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