大约有 5,000 项符合查询结果（耗时：0.0254秒） [XML]
Why does the C# compiler go mad on this nested LINQ query?
...yzed, compiles without issue:
static void Main()
{
var x = Enumerable.Range(0, 1).Sum(a);
}
private static int a(int a)
{
return Enumerable.Range(0, 1).Sum(b);
}
private static int b(int b)
{
return Enumerable.Range(0, 1).Sum(c);
}
private static int c(int c)
{
return Enumerable.Ra...
Increasing the maximum number of TCP/IP connections in Linux
...beit a little differently.
On the client side:
Increase the ephermal port range, and decrease the tcp_fin_timeout
To find out the default values:
sysctl net.ipv4.ip_local_port_range
sysctl net.ipv4.tcp_fin_timeout
The ephermal port range defines the maximum number of outbound sockets a host can...
Many-to-many relationship with the same model in rails?
... information.
TL;DR
# user.rb
has_many :friendships, :foreign_key => "user_id", :dependent => :destroy
has_many :occurances_as_friend, :class_name => "Friendship", :foreign_key => "friend_id", :dependent => :destroy
..
# friendship.rb
belongs_to :user
belongs_to :friend, :class_n...
What does enumerate() mean?
... one purpose, which doesn't cover enumerate.
– ShadowRanger
Feb 20 '19 at 14:54
add a comment
|
...
Pythonic way to check if a list is sorted or not
...aw is looking for. Here is the one liner:
all(l[i] <= l[i+1] for i in xrange(len(l)-1))
For Python 3:
all(l[i] <= l[i+1] for i in range(len(l)-1))
share
|
improve this answer
|
...
UnicodeEncodeError: 'ascii' codec can't encode character u'\xa0' in position 20: ordinal not in rang
...
In case someone else gets confused by this, I found a strange thing: my terminal uses utf-8, and when I print my utf-8 strings it works nicely. However when I pipe my programs output to a file, it throws a UnicodeEncodeError. In fact, when output is redirected (to a file or a pipe...
SQL - The conversion of a varchar data type to a datetime data type resulted in an out-of-range valu
...s!
For example:
September 31, 2015 does not exist.
EXEC dbo.SearchByDateRange @Start = '20150901' , @End = '20150931'
So this fails with the message:
Error converting data type varchar to datetime.
To fix it, input a valid date:
EXEC dbo.SearchByDateRange @Start = '20150901' , @End = '20150...
How to use filter, map, and reduce in Python 3
...def f(x): return x % 2 != 0 and x % 3 != 0
...
>>> list(filter(f, range(2, 25)))
[5, 7, 11, 13, 17, 19, 23]
>>> def cube(x): return x*x*x
...
>>> list(map(cube, range(1, 11)))
[1, 8, 27, 64, 125, 216, 343, 512, 729, 1000]
>>> import functools
>>> def add(...
Does PNG contain EXIF data like JPG?
...nk in PNG images.
Original: ImageMagick stores EXIF information in a PNG "Raw profile type APP1" zTXt chunk when converting from JPEG images. This method of storing EXIF in PNG images is also supported by ExifTool (and I believe Exiv2 too), but it is not part of the PNG or EXIF specification.
...
Vagrant ssh authentication failure
... vagrant@localhost -p 2222
then copy the public key content from https://raw.githubusercontent.com/mitchellh/vagrant/master/keys/vagrant.pub to the authorised_keys file with the following command
echo "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6NF8iallvQVp22WDkTkyrtvp9eWW6A8YVr+kz4TjGYe7gHzIw+niNltGEFH...