大约有 13,700 项符合查询结果（耗时：0.0401秒） [XML]
Only read selected columns
...,Apr,May,Jun from file",
sep = "\t")
3) With the read_*-functions from the readr-package:
library(readr)
dat <- read_table("data.txt",
col_types = cols_only(Year = 'i', Jan = 'i', Feb = 'i', Mar = 'i',
Apr = 'i', May...
Chained method calls indentation style in Python [duplicate]
...method names get longer and as methods start taking arguments:
return some_collection.get_objects(locator=l5) \
.get_distinct(case_insensitive=True) \
.filter(predicate=query(q5)) \
.values()
PEP 8 is intend to be interpreted with ...
C-like structures in Python
...uct(NamedTuple):
foo: str
bar: int
baz: list
qux: User
my_item = MyStruct('foo', 0, ['baz'], User('peter'))
print(my_item) # MyStruct(foo='foo', bar=0, baz=['baz'], qux=User(name='peter'))
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When should I use ugettext_lazy?
I have a question about using ugettext and ugettext_lazy for translations.
I learned that in models I should use ugettext_lazy , while in views ugettext.
But are there any other places, where I should use ugettext_lazy too? What about form definitions?
Are there any performance diffrences betwe...
SQL Server Escape an Underscore
...IKE keyword and the [ ] wildcard characters.
For your case:
... LIKE '%[_]d'
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How do I inspect the view hierarchy in iOS?
...
I've got: error: cannot find interface declaration for '$__lldb_objc_class' any ideas? (lldb) po [[UIWindow keyWindow] recursiveDescription] error: cannot find interface declaration for '$__lldb_objc_class' error: cannot find interface declaration for '$__lldb_objc_class' error:...
Adding a cross-reference to a subheading or anchor in another page
... general :ref: directive, documented here. They give this example:
.. _my-reference-label:
Section to cross-reference
--------------------------
This is the text of the section.
It refers to the section itself, see :ref:`my-reference-label`.
Although the general hyperlinkin...
What should my Objective-C singleton look like? [closed]
... below, I think you should be doing:
+ (id)sharedFoo
{
static dispatch_once_t once;
static MyFoo *sharedFoo;
dispatch_once(&once, ^ { sharedFoo = [[self alloc] init]; });
return sharedFoo;
}
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ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.al
...rrays causes the two arrays to be evaluated in boolean context (by
calling __bool__ in Python3 or __nonzero__ in Python2).
Your original code
mask = ((r["dt"] >= startdate) & (r["dt"] <= enddate))
selected = r[mask]
looks correct. However, if you do want and, then instead of a and b u...
Does C# have extension properties?
...{
private static readonly ConditionalWeakTable<Person, Employee> _employees =
new ConditionalWeakTable<Person, Employee>();
public decimal Salary
{
get
{
// `this` is the instance of Person
return _employees.GetOrCreate(this...