如何使用textscan()从MATLAB中的.txt文件读取逗号分隔的值?

问题描述

我有一个.txt文件，其中的行由三个元素组成，一个单词和两个数字，以逗号分隔.

I have a .txt file with rows consisting of three elements, a word and two numbers, separated by commas.

例如:

a,142,5
aa,3,0
abb,5,0
ability,3,0
about,2,0

我想读取文件，并将单词放在一个变量中，第一个数字放在另一个变量中，第二个数字放在另一个变量中，但是我在textscan上遇到问题.

I want to read the file and put the words in one variable, the first numbers in another, and the second numbers in another but I am having trouble with textscan.

这是我到目前为止所拥有的:

This is what I have so far:

File = [LOCAL_DIR 'filetoread.txt'];
FID_File = fopen(File,'r');
[words,var1,var2] = textscan(File,'%s %f %f','Delimiter',',');
fclose(FID_File);

我似乎无法弄清楚如何在textscan中使用定界符.

I can't seem to figure out how to use a delimiter with textscan.

推荐答案

horchler确实是正确的.您首先需要使用 fopen 打开文件，文件ID/指向实际文件的指针.然后，您可以将其与 textscan 一起使用.另外，您实际上只需要一个输出变量，因为一旦使用textscan，每个列"将作为一个单独的列放置在单元格数组中.您还需要将定界符指定为字符，因为这是用来分隔列的内容.这是通过使用textscan中的Delimiter选项来完成的，并且您将,字符指定为定界符.使用 fclose .

horchler is indeed correct. You first need to open up the file with fopen which provides a file ID / pointer to the actual file. You'd then use this with textscan. Also, you really only need one output variable because each "column" will be placed as a separate column in a cell array once you use textscan. You also need to specify the delimiter to be the , character because that's what is being used to separate between columns. This is done by using the Delimiter option in textscan and you specify the , character as the delimiter character. You'd then close the file after you're done using fclose.

这样，您只需执行以下操作:

As such, you just do this:

File = [LOCAL_DIR 'filetoread.txt'];
f = fopen(File, 'r');
C = textscan(f, '%s%f%f', 'Delimiter', ',');
fclose(f);

请注意，格式化字符串没有空格，因为定界符标志将完成这项工作.不要添加任何空格. C将包含一个列的单元格数组.现在，如果您想将列拆分为单独的变量，只需访问正确的单元格即可:

Take note that the formatting string has no spaces because the delimiter flag will take care of that work. Don't add any spaces. C will contain a cell array of columns. Now if you want to split up the columns into separate variables, just access the right cells:

names = C{1};
num1 = C{2};
num2 = C{3};

通过将您在帖子中提供的文本放入名为filetoread.txt的文件中，这些变量现在看起来像:

These are what the variables look like now by putting the text you provided in your post to a file called filetoread.txt:

>> names

names =

    'a'
    'aa'
    'abb'
    'ability'
    'about'

>> num1

num1 =

   142
     3
     5
     3
     2

>> num2

num2 =

     5
     0
     0
     0
     0

请注意，names是名称的单元格数组，因此只需执行n = names{ii};即可访问正确的名称，其中ii是您要访问的名称.您将使用普通的索引符号(即n = num1(ii);或n = num2(ii);)访问其他两个变量中的值.

Take note that names is a cell array of names, so accessing the right name is done by simply doing n = names{ii}; where ii is the name you want to access. You'd access the values in the other two variables using the normal indexing notation (i.e. n = num1(ii); or n = num2(ii);).

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