# Creating a variable from part of a string

2 ビュー (過去 30 日間)
Benjamin 2018 年 11 月 7 日

I have a string:
x='dr_1e-2_A1_OFF_A2_OFF.txt';
Is there a way to create variables from this string?
How can I set
dr = 1e-2
by only referring to the string? How can I set
A1 = 0 (since Off)
by only referring to the string?
Then if I want to create a title from the variables, could I?
Like:
title('dr = ' insert dr variable )
##### 1 件のコメント表示非表示 なし
Stephen Cobeldick 2018 年 11 月 7 日
"Then if I want to create a title from the variables, could I?"
You certainly could... but this is not recommended. Magically creating variable names is one way that beginners force themselves into writing slow, complex, buggy code which is hard to debug. Read this to know why:

サインインしてコメントする。

### 採用された回答

Stephen Cobeldick 2018 年 11 月 7 日

I recommend that you use a structure instead of magically accessing variable names:
>> x = 'dr_1e-2_A1_OFF_A2_OFF.txt';
>> [~,N] = fileparts(x);
>> C = regexp(N,'_','split');
>> S = struct(C{:});
>> S.dr
ans = 1e-2
>> S.A1
ans = OFF
>> S.A2
ans = OFF
You can easily add a conversion to numeric as well:
>> [~,N] = fileparts(x);
>> C = regexp(N,'_','split');
>> V = str2double(C);
>> X = ~isnan(V);
>> C(X) = num2cell(V(X));
>> S = struct(C{:});
>> S.dr
ans = 0.010000
"Then if I want to create a title from the variables,could I?"
##### 3 件のコメント表示非表示 2 件の古いコメント
James Tursa 2018 年 11 月 7 日
Yikes! The rest of my edited comment didn't make it, re the splitting and struct stuff ...

サインインしてコメントする。

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by