大约有 12,000 项符合查询结果（耗时：0.0410秒） [XML]
partial string formatting
...ct):
def __missing__(self, key):
return "{" + key + "}"
s = '{foo} {bar}'
formatter = string.Formatter()
mapping = FormatDict(foo='FOO')
print(formatter.vformat(s, (), mapping))
printing
FOO {bar}
Of course this basic implementation only works correctly for basic cases.
...
Can I call a base class's virtual function if I'm overriding it?
Say I have classes Foo and Bar set up like this:
7 Answers
7
...
error: request for member '..' in '..' which is of non-class type
...
Foo foo2();
change to
Foo foo2;
You get the error because compiler thinks of
Foo foo2()
as of function declaration with name 'foo2' and the return type 'Foo'.
But in that case If we change to Foo foo2 , the compiler ...
Adding 'serial' to existing column in Postgres
...ok at the following commands (especially the commented block).
DROP TABLE foo;
DROP TABLE bar;
CREATE TABLE foo (a int, b text);
CREATE TABLE bar (a serial, b text);
INSERT INTO foo (a, b) SELECT i, 'foo ' || i::text FROM generate_series(1, 5) i;
INSERT INTO bar (b) SELECT 'bar ' || i::text FROM ...
Is it possible to override JavaScript's toString() function to provide meaningful output for debuggi
...You can override toString in Javascript as well. See example:
function Foo() {}
// toString override added to prototype of Foo class
Foo.prototype.toString = function() {
return "[object Foo]";
}
var f = new Foo();
console.log("" + f); // console displays [object Foo]
See this discussi...
How does the “final” keyword in Java work? (I can still modify an object.)
...
try to do t.foo = new ArrayList(); in the main method and you will get compilation error...the reference foo is binded to just one final object of ArrayList...it cannot point to any other ArrayList
– Code2Interface
...
How to test if list element exists?
...ome effort) contain NULL elements, it might not be enough to check is.null(foo$a). A more stringent test might be to check that the name is actually defined in the list:
foo <- list(a=42, b=NULL)
foo
is.null(foo[["a"]]) # FALSE
is.null(foo[["b"]]) # TRUE, but the element "exists"...
is.null(foo...
How to use sed to replace only the first occurrence in a file?
...
# sed script to change "foo" to "bar" only on the first occurrence
1{x;s/^/first/;x;}
1,/foo/{x;/first/s///;x;s/foo/bar/;}
#---end of script---
or, if you prefer: Editor's note: works with GNU sed only.
sed '0,/foo/s//bar/' file
Source
...
Difference between staticmethod and classmethod
...of example 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)
...
Difference between 'struct' and 'typedef struct' in C++?
...entifiers (for typedef and other identifiers).
If you just said:
struct Foo { ... };
Foo x;
you would get a compiler error, because Foo is only defined in the tag namespace.
You'd have to declare it as:
struct Foo x;
Any time you want to refer to a Foo, you'd always have to call it a struc...