Plot histograms in python with matplotlib

Suppose we have a file theta.dat which has 1000 lines and each line has a angle value. Its first 10 lines are as follows.

100.35766
105.05182
112.56954
119.66241
125.35966
127.44947
125.47673
121.08910
118.00765
117.77907

How to plot a histogram figure in python with matplotlib with the file theta.dat?

We put this file in the home directory, thus the position is ~/theta.dat.
Then , we plot in Enthought Canopy Graphical Environment! One can download and install it in Software Manager. If we open it, the window looks like this.

f0

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How to use USB Audio cards on Raspberry Pi 3 (jessie)

A few days ago,I bought a USB Audio card.

I used one night to figure out how to configure the device on Raspberry Pi. I searched a lot of material, and I found many of them are outdated. Lots of people said to changed "/etc/modprobe.d/alsa-base.conf", but in jessie , the file dose not exist.

The files I changed are as follows and these settings works for me:
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Working in Linux 02: Jtext2code–Use Python to make a QR code generator

Sometimes, I need copy some links or text from computer to my smart phone.  It's such a bad experience to type all of the contents by myself. So I made a tool  in Linux called "Jtext2code", which  can  generate a QR code according to the text you choose. Use your smart phone application like Scanner to scan the picture generated, you can get the information you choose easily.

test

Let's build this.
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Solution for the Error “*** is not in the sudoers file. This incident will be reported. “

On the Raspbian system, when I created a new user with the commands
#useradd gang
There is no directory named "gang" under the home directory. When I login as a user (gang) and want to use the sudo command to create a main directory for myself, I saw the error "gang is not in the sudoers file. This incident will be reported. " This error implies that I have to edit the sudoers file to give myself the privilege to use sudo. To have the root privilege, I need to do as follows.
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Linux下使用Keil MDK 开发TM4C123G LaunchPad

Using Keil MDK develop TM4C123G LaunchPad in LinuxMint

Linux下有原生的Code Composer Studio (CCS)可以开发德州仪器的TM4C123G LaunchPad,用起来也很方便。但是我自己在edx上面上了一门课程叫做 “Embedded System --Shape the World”。课程用的是Keil集成开发环境。然而Keil没有Linux的版本,在上课的时候我是用Virtual Box 虚拟了一个Windows XP完成了课程。课程结束之后我参考网络上一些博文结合自己的经验,实现了利用wine安装keil,并成功编译代码,烧写到LaunchPad中。

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编译含.eps图片的Tex文件时遇到的问题

One solution of "Package pdftex.def Error: File 'eps-converted-to.pdf' not found

The problem:
In Textstudio, when I compile a  tex file including a .eps file, I meet  a error like this:
Error:  ! Package pdftex.def Error: File `P_ba_at_t-eps-converted-to.pdf' not found.
Here is one solution I found from web. MichaelChirico answered this question. The answer is as follows.

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