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How to read specific lines from sparkContext

由 半城伤御伤魂 提交于 2019-12-07 03:19:30
问题 Hi I am trying to read specific lines from a text file using spark. SparkConf conf = new SparkConf().setAppName(appName).setMaster(master); sc = new JavaSparkContext(conf); JavaRDD<String> lines = sc.textFile("data.txt"); String firstLine = lines.first(); It can used the .first() command to fetch the first line of the data.text document. How can I access Nth line of the document? I need java solution. 回答1: Apache Spark RDDs are not meant to be used for lookups. The most "efficient" way to get

Changing font in a two line figure title

由 末鹿安然 提交于 2019-12-07 01:03:19
问题 I want to write my figure title in two lines in a way that I can change the text properties of both lines separately. I found: title(['\bf{first line}' char(10) '\rm{second line}']) which makes the first line bold. But how can I change the font size for first line? 回答1: title(['\fontsize{20pt}\bf{first line}' char(10) '\fontsize{10pt}\rm{second line}']) I found this syntax hidden in the docs: http://www.mathworks.com/help/matlab/creating_plots/adding-text-annotations-to-graphs.html#f0-19466

make nstextfield single line

由 六眼飞鱼酱① 提交于 2019-12-06 19:07:52
问题 how to make NSTextField really single line? I created a text field programmatically. when the return key is pressed, all text is selected. but I can still paste multiple lines of text. And when I press Arrow-right or Arrow down, it scroll to the next line. There aren't these issues if I use IB and set the "use single line mode", but I couldn't find the right method to set it programmatically. 回答1: Have you tried telling the field's cell to set whether it uses single-line mode? [myTextField

Behavior of __LINE__ in inline functions

由 狂风中的少年 提交于 2019-12-06 17:40:45
问题 I have a macro that passes the line number and file name to an error handler: #define SYSTEM_FAILURE (error_code, comment) \ System_Failure((error_code), (comment), __LINE__, __FILE__); How will the __LINE__ be resolved when used inside an inlined function? file.h: inline int divide(int x, int y) { if (y == 0) { SYSTEM_FAILURE(ENUM_DIVIDE_BY_ZERO, "divide by zero error"); } return x/y; } Will __LINE__ contain the line number within the header file, or the line number of the source file where

Read a text file line by line into strings

由 微笑、不失礼 提交于 2019-12-06 17:04:00
问题 How do I read the contents of a text file line by line into String without using a BufferedReader ? For example, I have a text file that looks like this inside: Purlplemonkeys greenGorilla I would want to create two strings , then use something like this File file = new File(System.getProperty("user.dir") + "\Textfile.txt"); String str = new String(file.nextLine()); String str2 = new String(file.nextLine()); That way it assigns str the value of "Purlplemonkeys" , and str2 the value of

Matlab code to draw a tangent to a curve

由 房东的猫 提交于 2019-12-06 16:25:35
I need to draw a tangent to a curve at a particular point (say the point is chosen by the user). I have written a code that allows the user to manually pick up two points and then a line is drawn between them. But I would like to automate the process. Can someone please suggest any algorithms/already implemented matlab codes to do so? Try the function below. Of course, it needs lots of tweaking to apply to your case, but I think this is roughtly what you want. function test hh = figure(1); clf, hold on grid on x = 0:0.01:2*pi; f = @(x) sin(x); fprime = @(x) cos(x); plot(x, f(x), 'r') axis

vertical-align对齐规则

由 折月煮酒 提交于 2019-12-06 16:20:34
起作用的前提条件 只能应用于内联元素以及 display 值为 table-cell 的元素。 vertical-align 属性只能作用在 display 计算值为 inline、inline- block，inline-table 或 table-cell 的元素上。因此，默认情况下，span、strong、 em等内联元素，img、button、input等替换元素，非 HTML 规范的自定义标签 元素，以及<td>单元格，都是支持 vertical-align 属性的，其他块级元素则不支持。 浮动和绝对定位会让元素块状化，从而让内联元素的vertical-align不生效 百分比 vertical-align 的百分比值是相对于 line-height 计算的 且是以line-height的基线为基础，vertical-align:0%和vertical-align：baseline效果一样 vertical-align：inline-block和baseline vertical-align 属性的默认值 baseline 在文本之类的内联元素那里就是字符 x 的下 边缘，对于替换元素则是替换元素的下边缘。但是，如果是 inline-block 元素则规则要 复杂了：一个 inline-block 元素，如果里面就是没有图文内容，或者 overflow 不是

“for line in file object” method to read files

由 本小妞迷上赌 提交于 2019-12-06 15:34:01
问题 I'm trying to find out the best way to read/process lines for super large file. Here I just try for line in f: Part of my script is as below: o=gzip.open(file2,'w') LIST=[] f=gzip.open(file1,'r'): for i,line in enumerate(f): if i%4!=3: LIST.append(line) else: LIST.append(line) b1=[ord(x) for x in line] ave1=(sum(b1)-10)/float(len(line)-1) if (ave1 < 84): del LIST[-4:] output1=o.writelines(LIST) My file1 is around 10GB; and when I run the script, the memory usage just keeps increasing to be

Given two points (x1,y1) (x2,y2), how can I compute N different points evenly lying on the line between the given points

由 天涯浪子 提交于 2019-12-06 14:12:47
问题 I have two points and I would like to compute n evenly distributed points on top of the line created by the given line. How could I perform this in c++? 回答1: Linear interpolation (affectionately called lerp by the Graphics community) is what you want. Given the end points it can generate the points lying in between with a parameter t . Let the end points be A (Ax, Ay) and B (Bx, By) . The vector spanning from A to B would be given by V = B − A = <Vx, Vy> L(t) = A + tV This essentially means

当用python读取几十万行文本时，会出现什么状况？

由 半腔热情 提交于 2019-12-06 14:09:28
前言 本文的文字及图片来源于网络,仅供学习、交流使用,不具有任何商业用途,版权归原作者所有,如有问题请及时联系我们以作处理。 作者：accumulate_zhang 我在使用python读取几十万行的文件中的数据，并构造字典，列表等数据结构时，再访问字典，列表时，一般都会出现内存不够的问题，然后只能循环读取几百行或者一定数量的行数来循环操作。 keyword_list=[line.strip() for line in open("keywords.txt",'r')] #f1=open("part_wiki_vec.txt",'r') f1=open("wiki_vectors.txt") f2=open("result.txt",'w') i=0 content=f1.readlines() while i < 1150: for line in content[ 300* i:300*( i+ 1)] : line= line.strip().split(' ') if line[ 0] in keyword_list: wordvec= ' ' .join( line) print wordvec f2.write( wordvec) # print line i+= 1 我是这样读取的？ 应该还有很多好的方法，比如多线程等等。如果你还不是很明白或者正在学习
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