大约有 7,000 项符合查询结果（耗时：0.0410秒） [XML]
Pandas - How to flatten a hierarchical index in columns
...(pd.__version__) # '0.23.4'
index = pd.MultiIndex.from_product(
[['foo', 'bar'], ['baz', 'qux']],
names=['a', 'b'])
print(index)
# MultiIndex(levels=[['bar', 'foo'], ['baz', 'qux']],
# codes=[[1, 1, 0, 0], [0, 1, 0, 1]],
# names=['a', 'b'])
Applying to_flat_ind...
MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
...: { _id: "some potentially existing id" },
update: {
$setOnInsert: { foo: "bar" }
},
new: true, // return new doc if one is upserted
upsert: true // insert the document if it does not exist
})
As $setOnInsert only affects documents being inserted, if an existing document is found, no...
Form inside a form, is that alright? [duplicate]
...gt;</form>
<div id="toolbar">
<input type="text" name="foo" form="saveForm" />
<input type="hidden" value="some_id" form="deleteForm" />
<input type="text" name="foo2" id="foo2" form="saveForm" value="success" />
<input type="submit" name="save" val...
Default value for field in Django model
...can set the default like this:
b = models.CharField(max_length=7,default="foobar")
and then you can hide the field with your model's Admin class like this:
class SomeModelAdmin(admin.ModelAdmin):
exclude = ("b")
sha...
Use of alloc init instead of new
...be using a different method, such as [[SomeObject alloc] initWithString: @"Foo"]. If you're used to writing this, you get in the habit of doing it this way and so [[SomeObject alloc] init] may come more naturally that [SomeObject new].
...
Understanding Python's “is” operator
...lly with certain objects.
E.g.
>>> class A(object):
... def foo(self):
... pass
...
>>> a = A()
>>> a.foo is a.foo
False
>>> id(a.foo) == id(a.foo)
True
Ref;
How to access property of anonymous type in C#?
...
Then from that you look up a property:
PropertyInfo p = t.GetProperty("Foo");
Then from that you can get a value:
object v = p.GetValue(o, null);
This answer is long overdue for an update for C# 4:
dynamic d = o;
object v = d.Foo;
And now another alternative in C# 6:
object v = o?.GetTy...
Why do you use typedef when declaring an enum in C++?
...02000000
};
you'll have to use it doing something like :
enum TokenType foo;
But if you do this :
typedef enum e_TokenType
{
blah1 = 0x00000000,
blah2 = 0X01000000,
blah3 = 0X02000000
} TokenType;
You'll be able to declare :
TokenType foo;
But in C++, you can use only th...
S3 Static Website Hosting Route All Paths to Index.html
...th (HTML5) browser history who want to host on S3.
Suppose a user visits /foo/bear at your S3-hosted static web site. Given David's earlier suggestion, redirect rules will send them to /#/foo/bear. If your application's built using browser history, this won't do much good. However your application ...
Dynamic Sorting within SQL Stored Procedures
... readable IMO:
SELECT
s.*
FROM
(SELECT
CASE @SortCol1
WHEN 'Foo' THEN t.Foo
WHEN 'Bar' THEN t.Bar
ELSE null
END as SortCol1,
CASE @SortCol2
WHEN 'Foo' THEN t.Foo
WHEN 'Bar' THEN t.Bar
ELSE null
END as SortCol2,
t.*
FROM
MyTable t) as...