在MATLAB中逐行读取文本文件 [英] Reading a text file in MATLAB line by line

问题描述

我有一个CSV文件，我想读取这个文件，并对每行进行一些预先计算，看看例如该行对我有用，如果是的话，我将其保存到一个新的CSV文件。
有人能给我一个例子吗？
更多细节这是我的数据如何：（string，float，float）数字是坐标。

I have a CSV file, I want to read this file and do some pre-calculations on each row to see for example that row is useful for me or not and if yes I save it to a new CSV file. can someone give me an example? in more details this is how my data looks like: (string,float,float) the numbers are coordinates.

ABC,51.9358183333333,4.183255
ABC,51.9353866666667,4.1841
ABC,51.9351716666667,4.184565
ABC,51.9343083333333,4.186425
ABC,51.9343083333333,4.186425
ABC,51.9340916666667,4.18688333333333

基本上我想保存一个新文件中距离大于50或50的行。字符串字段也应该被复制。
感谢

basically i want to save the rows that have for distances more than 50 or 50 in a new file.the string field should also be copied. thanks

推荐答案

您可以使用 XLSREAD 来完成此操作。首先将上面的示例数据放在一个文件'input_file.csv'中，这里是一个如何获取数值，文本值和原始数据的示例来自 XLSREAD 的三个输出中的文件：

You could actually use XLSREAD to accomplish this. After first placing your sample data above in a file 'input_file.csv', here is an example for how you can get the numeric values, text values, and the raw data in the file from the three outputs from XLSREAD:

>> [numData,textData,rawData] = xlsread('input_file.csv')

numData =     %# An array of the numeric values from the file

   51.9358    4.1833
   51.9354    4.1841
   51.9352    4.1846
   51.9343    4.1864
   51.9343    4.1864
   51.9341    4.1869


textData =    %# A cell array of strings for the text values from the file

    'ABC'
    'ABC'
    'ABC'
    'ABC'
    'ABC'
    'ABC'


rawData =     %# All the data from the file (numeric and text) in a cell array

    'ABC'    [51.9358]    [4.1833]
    'ABC'    [51.9354]    [4.1841]
    'ABC'    [51.9352]    [4.1846]
    'ABC'    [51.9343]    [4.1864]
    'ABC'    [51.9343]    [4.1864]
    'ABC'    [51.9341]    [4.1869]

需要对数字数据，然后使用 XLSWRITE 。例如：

You can then perform whatever processing you need to on the numeric data, then resave a subset of the rows of data to a new file using XLSWRITE. Here's an example:

index = sqrt(sum(numData.^2,2)) >= 50;  %# Find the rows where the point is
                                        %#   at a distance of 50 or greater
                                        %#   from the origin
xlswrite('output_file.csv',rawData(index,:));  %# Write those rows to a new file

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