北航大学计算机基础实验7

实验7 科学计算与绘图实验报告学号：17374347姓名：周京成日期：2019/5/161. 实验目的(1)利用 NumPy 进行科学计算;(2)利用 Matplotlib 绘制基本图像。

2. 实验步骤（详述每一个子实验的关键语法及其实现）2.1 实验任务7-1import numpy as npimport matplotlib.pyplot as pl #导入所需包x = [1, 1.2, 1.4, 1.46, 1.65, 1.89, 2, 2.35, 2.47, 2.59, 2.78, 2.9, 3, 3.29, 3.48, 3.69, 3.91, 4, 4.19, 4.44, 4.68,4.87,5] # Make an array of x valuesy = [0, 3.064, 3.594, 3.439, 2.417, 0.713, 0, -1.342, -1.417, -1.306, -0.827, -0.395, 0, 1.04, 1.392, 1.273, 0.496, 0,-1.279, -2.978, -3.605, -2.349, 0] # Make an array of y values for each x valuex1=np.linspace(1,5,1000) #x列z=np.polyfit(x,y,5) #返回多项式系数列表f=np.poly1d(z) #返回多项式函数y1=f(x1) #得到y值pl.plot(x,y,'ro--',label='$original line$',linewidth=1) #折线图pl.plot(x1,y1,label='$smooth line$',linewidth=2) #多项式图pl.xlabel('x') #横轴pl.ylabel('f(x)') #纵轴pl.legend() #图例pl.show() #图2.2 实验任务7-2import numpy as npn=int(input())list1=[] #存储训练样本for i in range(n):list1.append(list(map(int,input().split()))) #存储训练样本过程list2=list(map(int,input().split()))#存储训练样本类别list3=list(map(int,input().split()))#存储测试数据list4=[] #存储距离for i in range(n):res=0for j in range(len(list1[0])):res+=(list1[i][j]-list3[j])**2list4.append(res)#存储距离过程min1=min(list4)#得到最小距离print(list2[list4.index(min1)])#得到最小距离对应类别2.3 实验任务7-3import matplotlib.pyplot as pltfrom matplotlib.font_manager import FontPropertiesimport numpy as npfont = FontProperties(fname='C:Window\Fonts\simkai.ttf')from pylab import mplmpl.rcParams['font.sans-serif'] = ['SimHei']str1 = "Diary One I am very lucky to be admitted to the class of Louis. Although it is a optional course ,I am expecting highly of it. I hope that I can get something useful about BEC through this course ,what is more ,laying a foundation for my further study on BEC. That is why I choose it. The first lesson is coming. Louis is really a person who are good activating every one of us. He let us speak out ,speak loudly ,which is contributing to our pour English. I think this is important to English learner .If you wants to learn English well, vocabulary and words are not far sufficient . In addition to those ,you must have bravery to speak out in public. you must speak out what you want to say to the various people that include your classmates ,your roommates, your teachers, your friends, and the foreigners .I have studied English for 9 years ,but I find I have difficulties in communicating with the other person .Maybe you can think what a bad think .It is shame to say this . Louis is a enthusiastic man .you can prove it when he introduced himself .it was very unforgettable for us .Because it was very impressing . Then he let us introduce ourselves. I saw someone stand to introduce himself. Honestly speaking ,I was jealous of them .Because they had the bravery of which I just be lack. Many times I was intending to stand up to ask questions and answer to him ,but I was finally drawing my hand back .May be I must have a look at myself. I think I must ask myself these questions: Why I afraid? Why I not stand? Why I not ask? Why I not put up my hands? Why I not answer the questions? I finally know life is short and time is swift. IF you miss the opportunities, the opportunities will miss you..Opportunity waits no man .I think this is what I get from the first class.I know everyone must have a control of the opportunities which are laid in front of him . I am very appreciating this chance that I can study business English. So I put my heart into it .I think I will get a lot of things and make many friends in the class. But I remember the old saying: If you want get ,you must give first .I will never forget this saying .I will give my enthusiasm, my energy, my attention , and my time into it . every one will see it . When Louis saied it was time for class.. I found time is swift. It could prove that I was very concentrating on the class. The first lesson is always unforgettable. Because it means that there is a new thing waiting for you . I like challenge ,so I like new things.I think today is a new day for me .Tomorrow is also new day for me .The day after tomorrow is also new. As for me ,every day is new day for me .Because I always remember one thing : let bygones be bygones. This is my first business English lesson. I like it Diary Two I think I have a good night today. I saw Louis again this evening. Because it was time for business English class. I dare to say you can see a smile in his face everyday . I can guess if somebody is in a bad mood ,he will get better when he sees Louis. According to the thirteen week’ study ,I have found Louis is a vigorous man. He is full of enthusiasm, and have a lot of energies which seem that they are not used out. Tonight Louis gave out some paper which was cut to pieces. These pieces came from a business letter. Louis had disorder these piece. Why he did that? What did he want us to do? A terriblely unsafe idea striked me. I could say for that moment I was in completely confusion. What was the next step? Louis then saied that it was a business letter which you must put them in right order with the other your group members. I had got it, but I found there was a bit difficulties for me . On taking the pieces of the letter ,all the group were busy in putting them in right place.. I thought It was a big pity that my group first came into a big problems. We could not decide which sentence was the fires one. What was a shame thing. When my group could not decide what to do ,I saw the other group seemed it was ready .I stood up and looked around. To my disappointment, they were also in confusion. It was very bad time for every of us. Louis stood in the front of the classroom. He seemed very happy to see that we were in completely confusion. When he came here , had a quick look at our group’ work ,not saying any word and walking away. Many times I wanted to ask for help ,but I withdrawed my hands. Many times I wanted to give up our pieces ,but I insisted . After 20 minutes ,Louis told us the right answer. Some sentences we put in right place first ,but some of them were in wrong place finally. Why? I thought it is confidence that we did not have. In addition , we did not trust our partners. We waste a lot of time in debating , which finally proved that it was useless. So I thought this was a helpful game. Every of us could profit a lot from it. I know ifone want to got some achievement ,he must learn how to cooperate with the other people. If he do the big thing alone ,I can guess he will not success. Today ,the consciousness of the group is more and more important than before. No matter where you go ,no matte what you do ,you can do without the other people. We must cultivate our consciousness of the group ,and have more and more trust on our partners. IF you can do this ,I think there is short way between you and success. In addition ,as far as I am concerned we must not give up when the thing is not ending. There is the saying goes this: the thing will not end until you give it up .I think it is very true. Don’t give up any thing ,if you can strive for it .Where there is a will ,there is a way ,which mean an long as you possesses a strong will ,you will certainly accomplish a task no matter how hard it is .In other words, one of words. one of the most important things to achieve success is a firm resolution. this is the case not only in our studies but also in all walks of life. As for me , I was not a strong –will person once upon a time .But I now I must change my idea. At the beginning of my college life, I was faced with some difficulties, including studying and personal sentiment. Once I lost my heart, but I did not give up .I stood up again . With a firm resolution and after a lot of failure ,I came through these. Diary Three It was a unhappy night. When I heared that we must write a 2000-word diary about business English class, I found I was in in dizzy. You may don’t know what is the concept of this? Since I entered into the fuzhou university ,all the words of English I wrote have not come to this number-2000.It is a terrible thing for me .Because I didn’t think I have many things to say .Even so .I didn’t think I can express them by writing.. There will be a oral test and paper text waiting for us .I am not good at spoken English . I don’t speak English very well. May be it relates to my diligence .I don't like opening my mouth, speaking English bravely. As a result , I was poor in my spoken English . The Learning of spoken English likes the learning of swimming. It is obvious that you can never swim if you dare not drop yourself into water. Swimming can only be learned through practice in water, which can make you get the feeling of water and make your motion correct and effective. Spoken English also likes this. You can not improve your oral English if you don't communicate wish other people. Only when you speaking English frequently can you improve your spoken English. Except for the homework and the boring test ,I think I like the business English class in heart. Louis was good at creating a happy and humorous atmosphere. He was always making the whole class seem interesting. I like this style of his very much.. Because I didn't fall asleep in class. Maybe it can say that it is a miracle for me. I have maked some friends with my classmate of the BEC since I went to the business English class. We have communicated some experiences about studying English since then, which have done me a great help to me. Throughout 13-week’studyingbusiness English ,I can not say that I know business English very well ,but I dare say this period studying will lay foundation for my further studying about business English. I have learned some businessletters ,some business words and some vocabularies which are use frequently in communicating in business. We completed the task that the Louis give together, and pointed out each other’ merits and deflects. We haved learn a lot by this way of improving our English level. We liked this and insisted in doing this. Maybe it also gave us a lot of funny. Once upon a time ,I thought ,my spoken English would never improve again. But since these weeks, through reading English article loudly and fluently in business class of Louis, I have found I improve my poor oral English a little. It was on my tongue when I wanted say something in English . Now it also likes that. But I am more brave than before when comes to speaking English .I think this is my great attainment from this business class. There are a few points that I want to share with everyone who likes English and wants to improve it: Don’t be shy to open your mouth; Don’t want to improve your English alone, you must communicate with others; Don’t only pay attention to the paper test; Practices makes perfect. This is what I want to say .Maybe it will do you a help in your improvement in your English. Finally ,let me have a hope. I hope that everyone of business English including Louis and my classmates will be happy everyday. ."#要处理得字符串list1 = [0] * 26 #26个字母对应数量str2 = str1.lower() #将字母变成小写for i in str2:if ord(i) >= 97 and ord(i) <= 122: #统计字母数量list1[ord(i) - 97] += 1for i in range(26):print(chr(i + 97), list1[i]) #输出字母对应数量ind = np.arange(26)fig, ax = plt.subplots()#建立子图rects1 = ax.bar(ind, list1, color='blue') #作图ax.legend((rects1[0],), (u' 字母分布 ',)) #加图例list5 = []for i in range(26):list5.append(chr((i + 97)))tul = tuple(list5) #做一个字母元组ax.set_xticks(ind)ax.set_xticklabels(tul) #修改横轴ax.set_xlabel(u'分类') #添加横项标签ax.set_ylabel(u'数值') #添加纵向标签ax.set_title(u'数据分析表') #添加标题plt.show() #展示图3. 实验总结（实验心得及体会，以及对本课程的建议等）感觉matplotlib多要使用才能熟，第一次用感觉不太好，对着老师得ppt还是可以艰难得做出来了。