targetURL := "http://www.example.com/one/two/three.json?output=four"
u, err := url.Parse(targetURL)
if err != nil {
panic(err)
}
fmt.Println(path.Base(u.Path))
// three.json
Example to download a file from url and save on local
io.Copy() read 32kb (maximum) from input and write to output reapeatly, so dont need worry about memory.
func DownloadFile(filepath string, url string) error {
// Create the file
out, err := os.Create(filepath)
if err != nil {
return err
}
defer out.Close()
// Get the data
resp, err := http.Get(url)
if err != nil {
return err
}
defer resp.Body.Close()
// Write the body to file
_, err = io.Copy(out, resp.Body)
if err != nil {
return err
}
return nil
}
reference: Code Example
var fibTests = []struct {
n int // input
expected int // expected result
}{
{1, 1},
{2, 1},
{3, 2},
{4, 3},
{5, 5},
{6, 8},
{7, 13},
}
source: 5 simple tips and tricks for writing unit tests in #golang
First of all, PHP Code Example. (PHP ≥ 7)
function isStriaghtFlush($d) {
$b = $f = 0;
$m = ['a'=>1,1=>10,'j'=>11,'q'=>12,'k'=>13];
foreach ($d as $a) {
$p = substr($a,-1);
$b |= 1<<(($m[$a[0]])??$a[0]);
$f = ($f===0||$f===$p) ? $p : 1;
}
$b = ($b << 3) | ($b >> 10);
foreach (range(0,13) as $i) {
if ((($b >> $i) & 31) == 31){
return [true, $f!=1];
}
}
return [false, false];
}
Explain:
A can be straight of A, 2, 3, 4, 5 and 10, J, Q, K A
There are total 14 ranks, when getting rank n from the $d, we set 1 of the n element in bitwise map.
If we could find any 5 continuously 1 in the bitwise map, then it’s straight. also if all faces are same, then it’s straight flush.
Example, cards: 10, J, Q, K, A
read 10, bitwise map: 0,0,0,1,0,0,0,0,0,0,0,0,0,0
read J, bitwise map: 0,0,1,1,0,0,0,0,0,0,0,0,0,0
read Q, bitwise map: 0,1,1,1,0,0,0,0,0,0,0,0,0,0
read K, bitwise map: 1,1,1,1,0,0,0,0,0,0,0,0,0,0
read A, bitwise map: 1,1,1,1,0,0,0,0,0,0,0,0,1,0
shift left 3 of bitwise map to 1,1,1,1,0,0,0,0,0,0,0,0,1,0,0,0,0
shift right 10 of bitwise map to 1,1,1,1
OR this two bitwise maps and get a new map 1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1,1
then we have 5 continuously 1, it’s straight.
Using Homebrew to install MariaDB, and got this eror when starting the server
$ mysql.server start
Starting MySQL
.161227 19:05:10 mysqld_safe Logging to '/usr/local/var/mysql/xxx.err'.
ERROR!
Mostly it is caused by previous installation of MySQL.
Manually remove /usr/local/var/mysql and reinstall MariaDB,
it will start normally.
You will get this kind of error message when you run brew services in tmux
/usr/local/Cellar/something/homebrew.mxcl.something.plist: Operation not permitted
How to fix it, just need install reattach-to-user-namespace
brew install reattach-to-user-namespace
Date Range Overlap
Only 2 conditions that overlap does not exist
|------ Date Range A ------|
|------ Date Range B ------|
or
|------ Date Range A ------|
|------ Date Range B ------|
That means start date A is later than end date B, or end data A is early than start date B.
Overlap exists if neither of them is true.
In rails we can create a scope to find all overlaps
scope :overlaps, -\>(start_date_, end_date_) do
where “((start_date \<= ?) and (end_date \>= ?))", end_date_, start_date_
end
reference:
http://stackoverflow.com/questions/325933/determine-whether-two-date-ranges-overlap
http://baodad.blogspot.com.au/2014/06/date-range-overlap.html
Ruby on Rails datepicker
Use bootstrap datepicker gem
Gemfile:
gem 'bootstrap-datepicker-rails'
Add this line to app/assets/stylesheets/application.scss
*= require bootstrap-datepicker3
Add this line to app/assets/javascripts/application.js
//= require bootstrap-datepicker
Add this line to template
<%= f.text_field :publish_at, "data-provide" => 'datepicker', "data-date-format" => "yyyy-mm-dd" %>
Install Arch Linux in Virtualbox
https://wiki.archlinux.org/index.php/Installation_guide
Pre-installation
Partition the disks
$ fdisk /dev/sda
boot
> n
> return (default primary)
> return (default partition 1)
> return (default first sector)
> +250M
swap
> n
> return (default primary)
> return (default partition 2)
> return (default first sector)
> +2G
/
> n
> return (default primary)
> return (default partition 3)
> return (default first sector)
> +2G
> return
/home
> n
> p (make primary)
> return (default first sector)
> return (default last sector)
make /dev/sda1 bootable
> a
> 1
make /dev/sda1 to swap type partition
> t
> 2
> 82
write table to disk and exit fdisk
> w
Format the partitions
format partitions
$ mkfs.ext4 /dev/sda1
$ mkfs.ext4 /dev/sda3
$ mkfs.ext4 /dev/sda4
make swap
$ mkswap /dev/sda2
mount swap
$ swapon /dev/sda2
Mount the partitions
$ mount /dev/sda3 /mnt
$ cd /mnt
$ mkdir boot home
$ mount /dev/sda1 boot
$ mount /dev/sda4 home
$ cd /
Installation
Select the mirrors
rankmirrors to make this faster (though it takes a while)
mv /etc/pacman.d/mirrorlist /etc/pacman.d/mirrorlist.orig
rankmirrors -n 6 /etc/pacman.d/mirrorlist.orig \>/etc/pacman.d/mirrorlist
pacman -Syy
Install the base packages
# install base packages (take a coffee break if you have slow internet)
pacstrap /mnt base base-devel
Configure the system
Generate an fstab file
$ genfstab -p /mnt >> /mnt/etc/fstab
Change root into the new system
$ arch-chroot /mnt
Set the hostname
$ echo [archlinux] > /etc/hostname
Set the time zone
$ ln -sf /usr/share/zoneinfo/Australia/Sydney /etc/localtime
uncomment the needed locales in /etc/locale.gen, then generate them with
$ locale-gen
Set locale preferences in /etc/locale.conf and possibly $HOME/.config/locale.conf
$ echo LANG=en_US.UTF-8 > /etc/locale.conf
Set the root password (root account ,not your account, we will create that later)
$ passwd
Install a bootloader
$ pacman -S grub-bios
$ grub-install /dev/sda
Create a new initial RAM disk
$ mkinitcpio -p linux
$ grub-mkconfig -o /boot/grub/grub.cfg
$ exit
Unmount the partitions
$ umount /mnt/home
$ umount /mnt/boot
$ umout /mnt
$ reboot
Until not, we finish installing archlinux, then we are going to setup the system.
Post-installation
After reboot, you might not be able to connect to innternet, run command to get ip address
$ dhcpcd
run it automatically when system starts
$ systemctl enable dhcpcd
turn on multi lib to install 32bit applications
$ vi /etc/pacman.conf
uncomment
[multilib](#)
Include = /etc/pacman.d/mirrorlist
update packages
$ pacman -Syy
$ pacman -Su
install x environment
$ pacman -S xorg-server xorg-xinit xorg-server-utils
intall mesa for 3d
$ pacman -S mesa
install virtualbox guest packages
$ pacman -S virtualbox-guest-utils
$ modprobe -a vboxguest vboxsf vboxvideo
create
$ vi /etc/modules-load.d/virtualbox.conf
add
vboxguest
vboxsf
vboxvideo
$ reboot
$ pacman -S xorg-twm xorg-xclock xterm
$ startx
create user to login
$ useradd -m -g users -G storage,power,wheel -s /bin/bash jma
$ passwd jma
$ visudo
allow user to run sudo command
find Uncomment to allow members of group wheel to execute any command and uncomment %wheel ALL=(ALL) ALL
Laravel Homestead commands:
Available commands:
destroy Destroy the Homestead machine
edit Edit the Homestead.yaml file
halt Halt the Homestead machine
help Displays help for a command
init Create a stub Homestead.yaml file
list Lists commands
resume Resume the suspended Homestead machine
run Run commands through the Homestead machine via SSH
ssh Login to the Homestead machine via SSH
status Get the status of the Homestead machine
suspend Suspend the Homestead machine
up Start the Homestead machine
update Update the Homestead machine imageThere is missing provision command
Solution is:
list all vagrant instance
$ vagrant global-status
id name provider state directory
-------------------------------------------------------------------------------------
6e1aa44 default virtualbox poweroff /Users/[whoami]/.composer/vendor/laravel/homestead
then run provision with id
$ vagrant provision 6e1aa4