大约有 10,000 项符合查询结果（耗时：0.0243秒） [XML]
Linux: copy and create destination dir if it does not exist
...ating any
missing intermediate directories.
Example:
/tmp $ mkdir foo
/tmp $ mkdir foo/foo
/tmp $ touch foo/foo/foo.txt
/tmp $ mkdir bar
/tmp $ cp --parents foo/foo/foo.txt bar
/tmp $ ls bar/foo/foo
foo.txt
share
...
Unsubscribe anonymous method in C#
... was to unsubscribe after the event was handled.
Example:
MyEventHandler foo = null;
foo = delegate(object s, MyEventArgs ev)
{
Console.WriteLine("I did it!");
MyEvent -= foo;
};
MyEvent += foo;
sh...
SQL keys, MUL vs PRI vs UNI
...s example has neither PRI, MUL, nor UNI:
mysql> create table penguins (foo INT);
Query OK, 0 rows affected (0.01 sec)
mysql> desc penguins;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+...
class
...
First, the class << foo syntax opens up foo's singleton class (eigenclass). This allows you to specialise the behaviour of methods called on that specific object.
a = 'foo'
class << a
def inspect
'"bar"'
end
end
a.inspect # =>...
p vs puts in Ruby
...
p foo prints foo.inspect followed by a newline, i.e. it prints the value of inspect instead of to_s, which is more suitable for debugging (because you can e.g. tell the difference between 1, "1" and "2\b1", which you can't when...
How can I generate Unix timestamps?
Related question is "Datetime To Unix timestamp", but this question is more general.
18 Answers
...
Getting “unixtime” in Java
Date.getTime() returns milliseconds since Jan 1, 1970. Unixtime is seconds since Jan 1, 1970. I don't usually code in java, but I'm working on some bug fixes. I have:
...
Automatically expanding an R factor into a collection of 1/0 indicator variables for every factor le
...the ade4 package :
R> library(ade4)
R> df <-data.frame(eggs = c("foo", "foo", "bar", "bar"), ham = c("red","blue","green","red"))
R> acm.disjonctif(df)
eggs.bar eggs.foo ham.blue ham.green ham.red
1 0 1 0 0 1
2 0 1 1 0 ...
How to check if a variable is set in Bash?
...-------------+-----------------+-----------------+
| Expression | FOO="world" | FOO="" | unset FOO |
| in script: | (Set and Not Null) | (Set But Null) | (Unset) |
+--------------------+----------------------+-----------------+-----------------+
| $...
How to get all subsets of a set? (powerset)
...
Active
Oldest
Votes
...