从字符串的元胞数组中读取特定字符

Question

我有一个维度为 1x6 的元胞数组，如下所示：

A = {'25_2.mat','25_3.mat','25_4.mat','25_5.mat','25_6.mat','25_7.mat'};

我想从 A{1} 中读取 '_' 之后的数字，即 2 我的示例

Answer 1

使用cellfun, strfind and str2double

out = cellfun(@(x) str2double(x(strfind(x,'_')+1:strfind(x,'.')-1)),A)

它是如何工作的？

This code simply finds the index of character one number after the occurrence of '_'. Lets call it as start_index. Then finds the character one number lesser than the index of occurrence of '.' character. Lets call it as end_index. Then retrieves all the characters between start_index and end_index. Finally converts those characters to numbers using str2double.

示例输入：

A = {'2545_23.mat','2_3.mat','250_4.mat','25_51.mat','25_6.mat','25_7.mat'};

输出：

>> out

out =

23     3     4    51     6     7

Answer 2

您可以使用大括号访问单元格的内容{...}。一旦可以访问内容，就可以使用索引来访问字符串的元素，就像访问普通数组一样。例如：

test = {'25_2.mat', '25_3.mat', '25_4.mat', '25_5.mat', '25_6.mat', '25_7.mat'}
character = test{1}(4);

如果你的字符串长度是可变的，你可以使用strfind来找到你想要的字符的索引。

Answer 3

假设数字是在_符号后的非负整数：使用正则表达式与lookbehind，然后从字符串转换为数字:

numbers = cellfun(@(x) str2num(x{1}), regexp(A, '(?<=\_)\d+', 'match'));