How to quickly solve python problems

May 24, 2014
Technology

问题

在txt里面打印1-10里面随机的9个数。

思路

如何生成随机数？

Google “generate random python” , 结果如下：
/images/python1.jpg

挨个看，马上你会发现下面这个网页有答案：
http://stackoverflow.com/questions/5555712/generate-a-random-number-in-python

启动终端试验之：

$ python
Python 2.7.6 (default, Feb 26 2014, 12:07:17) 
[GCC 4.8.2 20140206 (prerelease)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from random import randint
>>> randint(2,9)
3
>>> randint(1,10)
9
>>> randint(1,10)
4

如何循环打印

照样Google, 搜索关键字” python loop times”,结果如下：
/images/python2.jpg
随便点点看，发现python自己的文档里就已经有很详细的关于loop的例子了:
https://wiki.python.org/moin/ForLoop

试验之:

>>> for x in range(0,3):
...     print "hello"
... 
hello
hello
hello

综合，得出答案

用for的实现:

>>> for x in range(0,9):
...     print random.randrange(1,10)
... 
2
5
3
7
9
4
7
3
1

发散到用while的实现(原代码见上面的wiki网页)

>>> x = 1
>>> while x < 10:
...     print random.randrange(1,10)
...     x += 1
... 
4
4
4
5
1
9
1
8
2

当然你还可以反着弄while:

>>> x = 10
>>> while x > 0:
等等等等，不提示了

Moving From Working PC to Own USB-Disk Based 5

May 24, 2014
Technology

Font Customization

Install following fonts:

$ sudo pacman -S wqy-bitmapfont  wqy-zenhei ttf-arphic-ukai ttf-arphic-uming ttf-fireflysung

And then for more beautiful font, refer to:
http://kkkttt.github.io/blog/2013/12/25/archlinuxzhong-wen-hua-wen-ti/

VIM Customization

Vim is my favorite editor, so maintain a configuration file is necessary for deploying it on various machines.

$ sudo pacman -S ctags

Then copy the default vimrc file from /usr/share/vim74/vimrc_example to your own directory, named it into .vimrc. Add folllowing lines into .vimrc file:

" Customization Start
set nu
set cursorline 
set cursorcolumn
"Enable syntax
syntax enable
syntax on
" colorscheme solarized
autocmd BufNewFile,BufReadPost *.ino,*.pde set filetype=cpp
"进行Tlist的设置
""TlistUpdate可以更新tags
map <F3> :silent! Tlist<CR> 
"按下F3就可以呼出了
let Tlist_Ctags_Cmd='ctags' "因为我们放在环境变量里，所以可以直接执行
let Tlist_Use_Right_Window=1 "让窗口显示在右边，0的话就是显示在左边
let Tlist_Show_One_File=0 "让taglist可以同时展示多个文件的函数列表，如果想只有1个，设置为1
let Tlist_File_Fold_Auto_Close=1 "非当前文件，函数列表折叠隐藏
let Tlist_Exit_OnlyWindow=1 "当taglist是最后一个分割窗口时，自动推出vim
let Tlist_Process_File_Always=0 "是否一直处理tags.1:处理;0:不处理。不是一直实时更新tags，因为没有必要
let Tlist_Inc_Winwidth=0
set fileencodings=utf8,cp936,gb18030,big5
"In visual mode, you can simply press ,x and Vim will filter your content
"through tidy.
:vmap ,x :%!tidy -q -i --show-errors 0<CR> "Auto command for clear the html files
:command Thtml :%!tidy -q -i --show-errors 0
:command Txml  :%!tidy -q -i --show-errors 0 -xml


" Setting up Vundle - the vim plugin bundler
    let iCanHazVundle=1
    let vundle_readme=expand('~/.vim/bundle/vundle/README.md')
    if !filereadable(vundle_readme)
        echo "Installing Vundle.."
        echo ""
        silent !mkdir -p ~/.vim/bundle
        silent !git clone https://github.com/gmarik/vundle ~/.vim/bundle/vundle
        let iCanHazVundle=0
    endif
    set rtp+=~/.vim/bundle/vundle/
    call vundle#rc()
    Bundle 'gmarik/vundle'
    Bundle 'tpope/vim-fugitive'
    Bundle 'taglist.vim'
    " Bundle 'molokai'
    "Add your bundles here
    "Bundle 'Syntastic' "uber awesome syntax and errors highlighter
    Bundle 'altercation/vim-colors-solarized' 
    Bundle 'https://github.com/tomasr/molokai.git'
    "T-H-E colorscheme
    "Bundle 'https://github.com/tpope/vim-fugitive' "So awesome, it should be illegal 
    "...All your other bundles...
    if iCanHazVundle == 0
        echo "Installing Bundles, please ignore key map error messages"
        echo ""
        :BundleInstall
    endif
" Setting up Vundle - the vim plugin bundler end

colorscheme molokai
set guifont=YaHei\ Consolas\ Hybrid\ 11.5

Then everything I want is OK.
Command for configurating vbundle:

BundleInstall
BundleSearch

Tree tool has been installed, for view the complex directory structure :

$ sudo pacman -S tree

Install arduino from yaourt.

$ yaourt -S arduino

This will also install avr-gcc.

NodeJS

Install via yaourt:

$ yaourt -S nodejs

Basic Tutorial:
http://localhost2/blog/2014/05/14/node-dot-js-quick-start/
Later I will add the “Chat-like” Terminal-emulator series, so this part could be enhanced.

Editor tools

Tools which used for writing articles.

$ sudo pacman -S blender dia inkscape scribus
$ yaourt yed
$ yaourt sublime
$ sudo pacman -S gedit
$ sudo pacman -S imagemagick

Awesome Configuration

Dmenu which used for run applications:

$ sudo pacman -S dmenu

Screen shot:

$ sudo pacman -S scrot

Edit the /usr/bin/mycapscr

[Trusty@~]$ cat /usr/bin/mycapscr 
 scrot -s '%Y_%m_%d_%H_%M_%S_$wx$h.jpg' -e 'mv $f ~/capscr/'

Other Tools

Tcpdump for capturing packets.

$ sudo pacman -S tcpdump

Whatpulse for recording key click times:

$ sudo yaourt -S whatpulse
$ sudo gpasswd -a Trusty input

Remote Desktop:

$ pacman -S rdesktop

Conky and Conky configuration file.

$ pacman -S conky

hex tool:

$ pacman -S ghex

Calculator:

$ pacman -S bc
$ pacman -S gnome-calculator

Nautlus:

$ pacman -S nautilus

rar:

$ pacman -S rar

autossh:

$ pacman -S autossh

cmake:

$ pacman -S cmake

cronie:

$ pacman -S connie

elinks:

$ pacman -S elinks

eog:

$ pacman -S eog

ethtool

$ pacman -S ethtool

expect:

$ pacman -S expect

feh:

$ pacman -S feh

gparted:

$ pacman -S gparted

ipython2:

$ pacman -S ipython2

ntfs-3g:

$ pacman -S ntfs-3g

sakura lilyterm:

$ pacman -S sakura lilyterm

tmux:

$ pacman -S tmux

w3m,lynx:

$ pacman -S w3m lynx

xclip:

$ pacman -S xclip

xlockmore:

$ pacman -S xlockmore

E-Book Tools

XPdf:

$ pacman -S xpdf

calibre:

$ pacman -S calibre

Rstudio:

$ yaourt rstudio-desktop-bin

pandoc(Problem!):

$ yaourt pandoc
# Notice, you have to add curl -k in /etc/makepkg.conf

briss(For cutting pdf into 6 inch):

$ yaourt briss

coolreader(For reading epub):

$ yaourt -S coolreader

Moving From Working PC to Own USB-Disk Based 4

May 23, 2014
Technology

Writing Blog

I use octopress for writing blog, so this time in USB system I also want to enable it.
Edit the /etc/hostname and name my computer into “USBArch”, because we want to setup the id_rsa.pub in next step.

$ ssh-keygen
$ cat ~/.ssh/id_rsa.pub

Copy the content and add it into the “https://github.com/settings/ssh”, Then use command ssh -T git@github.com to verify if you can successfully be authenticated.

$ git clone git@github.com:kkkttt/debian_octopress.git
$ git clone git@github.com:kkkttt/herokublog.git

Now the repository is OK, but the ruby environment should be set.

$ curl -L https://get.rvm.io | bash -s stable
$ rvm use 1.9.3
# log out the terminal and log in again
$ rvm rubygems latest
$ cdheroku
# Choose yes, trust the .rvmrc
$ gem install bundler
$ bundle install

Test the rake command:

$ rake generate && rake deploy

OK, Then we can octopress for writing blogs.

WebServer

We will use xampp for webserver, because it’s very convinient to configure. Login as root, then:

# yaourt xampp

The detailed configuration steps could be viewed at:
http://kkkttt.github.io/blog/2014/04/23/deploy-xampp-on-archlinux/

In fact here I met a very strange problem, it seems if I put the whole blog under /home/Trusty/code, then the browser will complains that 403, so here I make a trick in rakefile(Which is used for generating the static website), add following line in rake generate

desc "Generate jekyll site"
task :generate do
  raise "### You haven't set anything up yet. First run `rake install` to set up an Octopress theme." unless File.directory?(source_dir)
  puts "## Generating Site with Jekyll"
  system "compass compile --css-dir #{source_dir}/stylesheets"
  system "jekyll"
  system "sudo cp -ar ./public/ /opt/ && sudo chown -R nobody /opt/public/ && sudo chgrp -R nobody /opt/public/ && sudo chmod 755 -R /opt/public/"
end

I don’t find another method, because xampp is too complex for configuring, we needn’t spend much more time on it.

Tomorrow I will setup the other language development environment.

Moving From Working PC to Own USB-Disk Based 3

May 22, 2014
Technology

Trouble Shooting

Unfortuately the qemu based pysical disk can’t bootup the machine correctly, so I re-intall the sytem on USB-Disk from the scratch. This time the problem appears as another: It can startup the machine, but failed to boot-up in qemu.
So I have to changed to use VirtualBox for booting the system.
Get the disk id via:

$ ls -l /dev/disk/by-id
lrwxrwxrwx 1 root root  9 May 22 14:45 usb-ATA_ST980811AS_xxxxxxxx-0:0 -> ../../sdb

Then use VirtualBox’s Internal command for creating the vmdk file, this vmdk file actually contains the physical disk.

$ VBoxManage internalcommands createrawvmdk -filename ./rawusb1.vmdk -rawdisk /dev/disk/by-id/usb-ATA_ST980811AS_XXXXXXXXXXX-0:0
RAW host disk access VMDK file ./rawusb1.vmdk created successfully.
$ sudo chown -R Trusty *

Now create a new virtual machine in virtualbox, use the newly created rawusb1.vmdk, bootup and you got the physical disk based virtual machine running.

Continue Install System

Install virtualenvironment via:

sudo pacman -S python2-virtualenv python-virtualenv python-virtualenvwrapper

In company machine, use pip freeze for getting all of the packages:

$ workon venv2
$ pip freeze>requirement.txt

In usb-disk based machine, install from the requirement.txt

$ mkdir .virtualenvs
# Add following lines into the .bashrc
export WORKON_HOME=~/.virtualenvs
source /usr/bin/virtualenvwrapper.sh
$ mkvirtualenv -p /usr/bin/python2.7 venv
$ pip install -r requirements.txt

After we update the installation, the package is the same as in computer machine.

ZSH

Install zsh and use it for replacing default bash:

$ sudo pacman -S zsh
$ chsh -s $(which zsh)

Now we can download the .zshrc from the company machine to usb disk based system.

Configure GIT Under Proxy

Setting the proxy and set it for git using proxy:

(venv)[Trusty@localhost ~]$ gcc -o connect connect.c 
(venv)[Trusty@localhost ~]$ sudo mv connect /usr/bin/
(venv)[Trusty@localhost ~]$ sudo chmod 777 /usr/bin/connect 
(venv)[Trusty@localhost ~]$ sudo vim /usr/bin/myproxy
(venv)[Trusty@localhost ~]$ sudo chmod 777 /usr/bin/myproxy
(venv)[Trusty@localhost ~]$ cat /usr/bin/myproxy 
/usr/bin/connect -H 1xx.xxx.xxx.xxx:2xxxx $@
(venv)[Trusty@localhost ~]$ git config --global core.gitproxy "/usr/bin/myproxy for *.*"
(venv)[Trusty@localhost ~]$ git config --global user.name "feixxxx"
(venv)[Trusty@localhost ~]$ git config --global user.email "feixxxx@gmail.com"

BlueTooth

Install blueman:

$ sudo pacman -S patch automake autoconf libtool 
$ yaourt blueman
# choose blueman-bzr
$ sudo pacman -S bluez-utils bluez-libs python2-pybluez
$ yaourt -S bluez4
$ yaourt pulseaudio-bluez4

Configure bluetooth:

$ sudo systemctl start bluetooth
$ sudo systemctl enable bluetooth
$ cat /etc/bluetooth/audio.conf

[General]
Enable=Socket

[A2DP]
SBCSources=1
$

Later bluemanager will be added into the awesome startup application.
The configuration is pretty complex, this is the start-point for settingup the bluetooth, later we will configure the bluetooth headset.

Tray items

$ sudo pacman -S udiskie wicd wicd-gtk

Awesome Customization

Download the themes from github:

$ sudo pacman -S hddtemp vicious
$ git clone https://github.com/Morley93/awesome-themes-3.5.git

Still have some problems. Need update.
Then get the customized awesome configuration file. Be sure to use the default, because later you can customize yourself.

Solve wicd error:
Error: Could not connect to wicd’s D-Bus interface

$ sudo pacman -R wicd wicd-gtk
$ sudo rm -rf /etc/wicd /var/log/wicd /etc/dbus-1/system.d/wicd*
$ sudo pacman -S wicd wicd-gtk
$ sudo pacman -Syu systemd-sysvcompat
$ sudo gpasswd -a Trusty users
$ sudo systemctl enable wicd
$ sudo systemctl start wicd

Now your wicd is OK for see.

udiskie2 problem, cannot start because lack of PyYAML:

$ sudo pacman -S python2-pip
$ sudo pip2 install PyYAML

Now seems all of your tray icons will be OK.

System Tools

Install the mlocate so we can use updatedb:

$ sudo pacman -S mlocate
$ sudo updatedb

Moving From Working PC To Own USB-Disk Based

May 21, 2014
Technology

Background

Since I want to hava a usb-based OS which could easily be taken by hand, I took this series for resarching how to finish this aim.

Preparation

ArchLinux iso file, USB-3.0 HardDisk, 80GB, later I will use a bigger one.

Qemu Script

I use qemu firstly to install the system. following is the configuraton file for qemu-i386:

#!/bin/bash
USERID=$(whoami)

# Get name of newly created TAP device; see https://bbs.archlinux.org/viewtopic.php?pid=1285079#p1285079
precreationg=$(/usr/bin/ip tuntap list | /usr/bin/cut -d: -f1 | /usr/bin/sort)
sudo /usr/bin/ip tuntap add user $USERID mode tap
postcreation=$(/usr/bin/ip tuntap list | /usr/bin/cut -d: -f1 | /usr/bin/sort)
IFACE=$(comm -13 <(echo "$precreationg") <(echo "$postcreation"))

# This line creates a random MAC address. The downside is the DHCP server will assign a different IP address each time
printf -v macaddr "52:54:%02x:%02x:%02x:%02x" $(( $RANDOM & 0xff)) $(( $RANDOM & 0xff )) $(( $RANDOM & 0xff)) $(( $RANDOM & 0xff ))
# Instead, uncomment and edit this line to set a static MAC address. The benefit is that the DHCP server will assign the same IP address.
# macaddr='52:54:be:36:42:a9'
  
qemu-system-i386 -net nic,macaddr=$macaddr -net tap,ifname="$IFACE" $*
  
sudo ip link set dev $IFACE down &> /dev/null
sudo ip tuntap del $IFACE mode tap &> /dev/null

Run the virtual machine like following:

$ ./run-qemu-i386 -hda /dev/sdc -m 1024 -boot d -cdrom  ./archlinux-2014.05.01

Installation Of ArchLinux

When your iso bootup, you will enter command-line, use following command for start the ssh :

# passwd root
# systemctl start sshd
# ifconfig 
# ssh root@10.0.0.240

Partition disk:

# fdisk /dev/sda
Command (m for help): p
Disk /dev/sda: 74.5 GiB, 80026361856 bytes, 156301488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xc001c001

Device    Boot Start       End   Blocks  Id System
/dev/sda1       2048 156301487 78149720  83 Linux

Command (m for help): d

Selected partition 1
Partition 1 has been deleted.

Command (m for help): n

Partition type:
   p   primary (0 primary, 0 extended, 4 free)
   e   extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-156301487, default 2048): 
Last sector, +sectors or +size{K,M,G,T,P} (2048-156301487, default 156301487): +1G

Created a new partition 1 of type 'Linux' and of size 1 GiB.

Command (m for help): t
Hex code (type L to list all codes): 82
Changed type of partition 'Linux' to 'Linux swap / Solaris'.

Command (m for help): n

Partition type:
   p   primary (1 primary, 0 extended, 3 free)
   e   extended
Select (default p): p
Partition number (2-4, default 2): 
First sector (2099200-156301487, default 2099200): 
Last sector, +sectors or +size{K,M,G,T,P} (2099200-156301487, default 156301487): 

Created a new partition 2 of type 'Linux' and of size 73.5 GiB.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@archiso ~ # fdisk -l /dev/sda

Disk /dev/sda: 74.5 GiB, 80026361856 bytes, 156301488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xc001c001

Device    Boot     Start       End   Blocks  Id System
/dev/sda1           2048   2099199  1048576  82 Linux swap / Solaris
/dev/sda2        2099200 156301487 77101144  83 Linux

Now your partition is ok, make filesystems.

# mkfs.ext4 /dev/sda2                                                             
root@archiso ~ # mkswap /dev/sda1
root@archiso ~ # swapon /dev/sda1

Now begin to install system:

# mount /dev/sda2 /mnt
# pacstrap /mnt base

Configuraion:

# genfstab -p /mnt >> /mnt/etc/fstab
# arch-chroot /mnt
sh-4.3# cat /etc/hostname 
FreeArch

sh-4.3# ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
# Uncomment the items in /etc/locale.gen, and run: 
sh-4.3# locale-gen
Generating locales...
  en_US.UTF-8... done
  en_US.ISO-8859-1... done
  zh_CN.GB18030... done
  zh_CN.GBK... done
  zh_CN.UTF-8... done
  zh_CN.GB2312... done
  zh_TW.EUC-TW... done
  zh_TW.UTF-8... done
  zh_TW.BIG5... done
Generation complete.

sh-4.3# mkinitcpio -p linux
sh-4.3# passwd root

Network Configuration:

sh-4.3# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 52:54:94:b5:12:24 brd ff:ff:ff:ff:ff:ff
sh-4.3# pacman -S dhcpcd
sh-4.3# systemctl enable dhcpcd@ens3
ln -s '/usr/lib/systemd/system/dhcpcd@.service' '/etc/systemd/system/multi-user.target.wants/dhcpcd@ens3.service'

BootLoad Configuration:

# pacman -S grub
# grub-install --target=i386-pc --recheck --debug /dev/sda
# grub-mkconfig -o /boot/grub/grub.cfg

Umount and reboot:

umount -R /mnt

Configuration Of System

Install openssh firstly, and net-tools for getting the ipaddress using ifconfig:

pacman -S openssh
systemctl enable sshd
systemctl start sshd
pacman -S net-tools

Now you can use terminal for getting to the qemu-based machine, and sshd service should be enabled always.

Quickly setup an account, because using root is a bad idea.

# useradd -m -g root -G audio -s /bin/bash Trusty
# pacman -S sudo
# visudo
##
## User privilege specification
##
root ALL=(ALL) ALL
Trusty ALL=(ALL) NOPASSWD: ALL
## Locale settings
# Defaults env_keep += "LANG LANGUAGE LINGUAS LC_* _XKB_CHARSET"
Defaults env_keep += "http_proxy https_proxy ftp_proxy ftps_proxy"

Now you can use the newly added username “Trusty” for login.

Install yaourt, add following lines into the file /etc/pacman.conf:

[archlinuxfr]
SigLevel = Never
Server = http://repo.archlinux.fr/$arch

Then update and install yaourt:

sudo pacman -Syu && sudo pacman -S yaourt

Next chapter we will begin to install softwares.

很惭愧，就做了一点微小的工作