问题描述
尝试比较和绘制两个不同长度的文件时遇到麻烦.在MATLAB中，我不知道如何在同一x轴上绘制两个不同长度的向量.由于一个文件缺少一些数据，因此我想创建一行并为相应的时间戳记留空白.以下是数据文件的示例:
I am running into trouble trying to compare and plot two files of different length. In MATLAB I do not know how to plot two vectors of different length in the same x-axis. As one file has some data missing, I want to create a row and put blank space for that corresponding time stamp. Here are samples of data files:
文件1:
date time T01 T02 T03 T04 T05
8/16/2009 0:00, 516.900024, 450.5, 465.200012, 546.799988, 539.700012
8/16/2009 0:10, 351.200012, 398.899994, 418.100006, 510.299988, 518.5
8/16/2009 0:30, 241.399994, 252.399994, 256, 360.600006, 386.5
8/16/2009 1:00, 184.199997, 154.300003, 143.899994, 236.600006, 244.399994
文件2:
date time T01 T02 T03 T04 T05
8/16/2009 0:00, 656.799988, 611.200012, 860.599976, 604.700012, 288.5
8/16/2009 0:10, 527.400024, 359.200012, 789.099976, 789.099976, 446.799988
8/16/2009 0:20, 431.5, 327.100006, 763.599976, 895.099976, 689.099976
8/16/2009 0:30, 328.399994, 301.700012, 824, 1037.099976, 955.299988
8/16/2009 0:40, 261.5, 332.200012, 811.700012, 962.200012, 915.599976
8/16/2009 0:50, 180.300003, 291.100006, 700.099976, 855.200012, 836.900024
8/16/2009 1:00, 294.399994, 281.399994, 731.299988, 881.700012, 666.200012
8/16/2009 1:10, 274.899994, 334.200012, 759.400024, 913.900024, 760.799988
我正在尝试按以下方式重新制作文件1:
I am trying to remake file 1 as follows:
8/16/2009 0:00, 516.900024, 450.5, 465.200012, 546.799988, 539.700012
8/16/2009 0:10, 351.200012, 398.899994, 418.100006, 510.299988, 518.5
8/16/2009 0:20, ,,,,
8/16/2009 0:30, 241.399994, 252.399994, 256, 360.600006, 386.5
8/16/2009 0:40, ,,,,
8/16/2009 0:50, ,,,,
8/16/2009 1:00, 184.199997, 154.300003, 143.899994, 236.600006, 244.399994
8/16/2009 1:10, ,,,,
有没有办法做到这一点?这将对我有很大帮助，因为我正在尝试根据时间戳链接两个文件.
Is there a way to do this? it would help me a lot as I am trying to link up 2 files based on time stamps.
p.s .:我正在尝试在MATLAB中使用ismember函数，并且遇到了各种各样的问题.
p.s.: I am trying to use the ismember function in MATLAB and am having all sorts of problems.
推荐答案
我假设您首先按照.如果您有时间戳记(使用 DATENUM )和存储在变量fileData1和fileData2中的两个文件中的数据，以下是一种简单的方法来绘制同一组轴上每个数据的数据(使用函数 PLOT 和 HOLD 命令):
I assume you are first reading data from the files as described in the answers to this question. If you have the time-stamps (converted using DATENUM) and data from the two files stored in variables fileData1 and fileData2, the following is a simple way to plot data from each on the same set of axes (using the function PLOT and the HOLD command):
t1 = fileData1(:,1); %# Time-stamps for file 1
d1 = fileData1(:,2); %# First column of data for file 1
plot(t1,d1,'ro-'); %# Plot data from file 1, using a red line with circles
hold on;
t2 = fileData2(:,1); %# Time-stamps for file 2
d2 = fileData2(:,2); %# First column of data for file 2
plot(t2,d2,'bo-'); %# Plot data from file 2, using a blue line with circles
上图中的每条线将具有不同数量的时间点(即圆形标记)，但每条线将是连续的(即不间断的)线.如果要在缺少时间戳的情节中显示中断，可以使用 NaN 值.如果您确定知道较小文件中的时间戳永远不会大于较大文件中的时间戳(即较小文件中的时间戳是时间戳的子集)则可以使用 ISMEMBER 如下:
Each line in the above plot will have a different number of time points (i.e. circle markers), but each will be a continuous (i.e. unbroken) line. If you want to show breaks in the plot where there are missing time-stamps, you can pad the data from file 1 with NaN values. If you know for sure that there are never time-stamps in the smaller file that aren't in the larger file (i.e. that the time-stamps in the smaller file are a subset of the time-stamps in the larger), then you can use the function ISMEMBER as follows:
newData = nan(size(fileData2)); %# New file 1 data, initialized to NaN
t = fileData2(:,1); %# Use the time-stamps from file 1
index = ismember(t,fileData1(:,1)); %# Find row indices of common time-stamps
newData(:,1) = t; %# Copy time-stamps
newData(index,:) = fileData1; %# Copy data
如果小文件中有 时间戳，而大文件中没有，则必须使用基于 INTERSECT 函数(如我对您其他相关问题的回答).
If there are time-stamps in the smaller file that aren't in the larger, then you will have to use a solution based on the INTERSECT function (as illustrated in my answer to your other related question).
现在，您可以使用以下方法绘制数据:
And now, you can plot the data using the following:
d1 = newData(:,2); %# First column of padded data for file 1
d2 = fileData2(:,2); %# First column of data for file 2
plot(t,d1,'ro-',t,d2,'bo-'); %# Plot both lines
以下是NaN填充在绘制时(使用一些随机生成的数据)所产生的差异的示例:
Here's a sample of the difference NaN-padding makes when plotting (using some randomly generated data):
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