Adding Text To Table Data

Question

Ben van Zon 2023-9-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2020901-adding-text-to-table-data

评论： Ben van Zon 2023-9-14

ct4004355_si_003.txt

I wanna give names to transitions in my file, but whenever I want to name something it changes to a numerical value or NaN.

So whenever the value is -1 -> P, 0 -> Q and 1 -> R.

FileName = 'ct4004355_si_003.txt';
T = readtable('ct4004355_si_003.txt', 'Delimiter','\t', 'TextType','string');
Rows = T(130:154,[1 2 3 4 5 6 11 12 13 14]);
Rows.Properties.VariableNames = ["Wavenumber [cm-1]", "Uncertainty", "v1u", "v2u", "L2u", "Ju", "v1l", "v2l", "L2l", "Jl"];
PR = Rows.Ju-Rows.Jl;
Rows = [Rows table(PR, 'VariableNames', {'Branch'}) ];
Rows.Branch(ismember(Rows.Branch, [-1])) = 'P'

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Ben van Zon 2023-9-14

25×11 table

Wavenumber [cm-1] Uncertainty v1u v2u L2u Ju v1l v2l L2l Jl Branch

_________________ ___________ ___ ___ ___ __ ___ ___ ___ __ ______

2051.5 0.01 0 1 1 5 0 0 0 6 80

2054 0.01 0 2 2 5 0 1 1 6 80

2057.4 0.01 0 2 0 1 0 1 1 2 80

2060.2 0.01 0 1 1 6 0 0 0 7 80

2061.7 0.01 0 1 1 5 0 0 0 6 80

: : : : : : : : : : :

2134.2 0.01 0 2 0 7 0 1 1 7 0

2134.9 0.01 0 1 1 4 0 0 0 5 80

2137 0.01 0 2 2 4 0 1 1 5 80

2140.3 0.01 0 1 1 4 0 0 0 5 80

2142.3 0.01 0 2 2 4 0 1 1 5 80

This is the result, instead of '80' I need a 'P'.

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Answer 1

Dyuman Joshi 2023-9-14

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2020901-adding-text-to-table-data#answer_1310026

在 MATLAB Online 中打开

ct4004355_si_003.txt

FileName = 'ct4004355_si_003.txt';
T = readtable('ct4004355_si_003.txt', 'Delimiter','\t', 'TextType','string');
Rows = T(130:154,[1 2 3 4 5 6 11 12 13 14]);
Rows.Properties.VariableNames = ["Wavenumber [cm-1]", "Uncertainty", "v1u", "v2u", "L2u", "Ju", "v1l", "v2l", "L2l", "Jl"];
PR = Rows.Ju-Rows.Jl;
Rows = [Rows table(PR, 'VariableNames', {'Branch'}) ];
str = 'PQR';
Rows.Branch = str(Rows.Branch+2)'
Rows = 25×11 table
Wavenumber [cm-1]Uncertaintyv1uv2uL2uJuv1lv2lL2lJlBranch________________________________________________________

         2051.5              0.01        0      1      1     5      0      0      0     6       P   
           2054              0.01        0      2      2     5      0      1      1     6       P   
         2057.4              0.01        0      2      0     1      0      1      1     2       P   
         2060.2              0.01        0      1      1     6      0      0      0     7       P   
         2061.7              0.01        0      1      1     5      0      0      0     6       P   
         2067.4              0.01        0      1      1     6      0      0      0     7       P   
           2074              0.04        0      2      2     5      0      1      1     6       P   
         2077.5              0.01        0      1      1     6      0      0      0     7       P   
         2079.4              0.01        0      1      1     5      0      0      0     6       P   
         2080.7              0.03        0      1      1     6      0      0      0     7       P   
         2089.3              0.01        1      1      1     3      1      0      0     4       P   
         2089.8              0.01        0      2      2     5      0      1      1     6       P   
         2094.2             0.015        0      2      2     5      0      1      1     6       P   
         2095.3              0.02        0      2      2     4      0      1      1     5       P   
         2096.6              0.01        0      1      1     5      0      0      0     6       P   
         2097.7              0.01        1      1      1     3      1      0      0     4       P   

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Dyuman Joshi 2023-9-14

在 MATLAB Online 中打开

> Explaination - When you convert the data type of a portion of data, (if the conversion is allowed) MATLAB retains the data type and changes the modified data to the original data type.

%Double numeric
y = 1:5
y = 1×5
     1     2     3     4     5
z = 'Yo'
z = 'Yo'
%Last 2 values changed to string, but the MATLAB converts the corresponding
%string to double numeric
y(end-1:end) = z
y = 1×5
     1     2     3    89   111
%Character vector
y = 'Maths is fun'
y = 'Maths is fun'
%1st 3 values changed to numeric, MATLAB converts the
%corresponding numbers to their character (ASCII) values
y(1:3) = [69 420 666]
y = 'EƤʚhs is fun'

If you want to change the data-type of variable corresponding to some value, over-write the whole array -

y = 1:5;
y = sprintf('%d', y)
y = '12345'

In your case, the original data was numeric. You modified some values to be a character ('P' to be exact), MATLAB converted it to the numerical value

double('P')
ans = 80

I over-wrote the whole data.

> P = -1, Q = 0, R = 1

can be changed to

P+2 = 1, Q+2 = 2, R+2 = 3

So, I used 1, 2, and 3 as indices, corresponding to 'P', 'Q' and 'R'.

Why change? Because indexing in MATLAB starts with 1.

> What if the values were different and the data was much bigger? Say -

P = -53, Q = 13, R = 0

%vec is only used to generate data
vec = [-53 0 13];
str = 'PQR';
%And this is the data we are working with
data = vec(randi(3,1,100))
data = 1×100
     0     0     0     0   -53   -53   -53   -53    13    13   -53    13     0     0   -53     0   -53     0    13     0     0    13   -53     0    13   -53     0    13    13     0
%Then get the unique values and corresponding indices
[arr,~,idx] = unique(data)
arr = 1×3
   -53     0    13
idx = 100×1
     2
     2
     2
     2
     1
     1
     1
     1
     3
     3
%And use the indices to change the values
data = str(idx)
data = 'QQQQPPPPRRPRQQPQPQRQQRPQRPQRRQPRRQQQQPQPPPRRPRRPRRRQQRQPRQQPRRQRPRPRQPRQQRQPQQPQRRRQRQPPQRQQPQRRQPQR'