For a certain condition, how to replace a numerical value with text

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mcm
mcm 2016-10-23
评论： Image Analyst 2016-10-23
For example: if x == 0 replace 0 by 'normal'

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回答（1 个）

John D'Errico
John D'Errico 2016-10-23
A numeric variable cannot contain text. So one element of a vector cannot be the word 'normal', while the remainder remains numeric. To do that you would need to convert a vector to a cell array, but then simple computations on the cell array are much less easy to do.
To do what you explicitly asked is trivial though:
if x == 0
x = 'normal';
end
  2 个评论
mcm
mcm 2016-10-23
编辑：Image Analyst 2016-10-23
But I do i change all the value for an array (UPDRS1997) of 1x50 different values ranging from 0 to 4.
pick_year = input('Pick a year: either 1997 or 2013: ')
if pick_year == 1997
load('UPDRS1997')
for x = UPDRS1997
if x == 0
x = 'normal'
elseif x == 1
x = 'slight'
elseif x == 2
x = 'mild'
elseif x == 3
x= 'moderate'
elseif x == 4
x = 'severe'
end
end
end
Image Analyst
Image Analyst 2016-10-23
If UPDRS1997 has 50 values in it, fine, but that code will overwrite x every time so it will have only the value that it has for UPDRS1997(end). Here is a better, more robust, general and flexible way:
pick_year = input('Pick a year: either 1997 or 2013: ')
filename = sprintf('UPDRS%d.mat', pick_year);
if exist(filename, 'file')
s = load(filename)
if pick_year == 1997
vec = s.UPDRS1997;
else
vec = s.UPDRS2013;
end
for k = 1 : length(vec)
if vec(k) == 0
x{k} = 'normal'
elseif vec(k) == 1
x{k} = 'slight'
elseif vec(k) == 2
x{k} = 'mild'
elseif vec(k) == 3
x{k} = 'moderate'
elseif vec(k) == 4
x{k} = 'severe'
end
end
else
message = sprintf('%s does not exist', filename);
uiwait(warndlg(message));
end
In this, the final result (badly named "x") is a cell array of 50 strings. It's not overwriting all the x like you did.

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