Problem stataments in Matlab
显示 更早的评论
Hi,
I would like to make a problem statement in Matalb, here are 3 columns, the 1st column is the user ID, the 2nd is (A/B) and 3rd is the combinations of $ and NIC.
(1) I wanted to count (a) how many many times $ has been pressed in total (b) count multiple $ as once pressed only by each user and total number of it.
(2) And in column 2, i wanted to check how many times the NIC has been pressed before $ pressed (so, 1st pressed: NIC, 2nd pressed: $) and count the total number of users.
I haven't used the Matalb for so long, so i would like to know how to do it...
Tim
采纳的回答
Dyuman Joshi
2022-5-19
Final answer, I have tested this code on my laptop
cd=0; %counting $
userd=[];
for i=1:size(T,1)
if isequal(char(T.Column2(i)),'$')
cd=cd+1; %number of '$' has been pressed.
userd=[userd char(T.Column1(i))];
end
end
uniqued=numel(unique(userd))
cnic=0; %counting NIC before $
usernic=[];
for j=1:size(T,1)-1
if isequal(char(T.Column2(j)),'NIC')&isequal(char(T.Column2(j+1)),'$')
cnic=cnic+1;
usernic=[usernic char(T.Column1(j))];
end
end
uniquenic=numel(unique(usernic))
更多回答（3 个）
Dyuman Joshi
2022-5-12
编辑：Dyuman Joshi
2022-5-13
I'm assuming that the data in Column 1 and Column 2 is char/strings.
%T is your table
cd=0; %counting $
userd=[];
for i=1:size(T,1)
if isequal(T.Column2(i),'$')
countd=countd+1; %number of '$' has been pressed.
userd=[userd T.Column1(i)];
end
end
uniqued=numel(unique(userd));
cnic=0; %counting NIC before $
usernic=[];
for j=1:size(T,1)-1
if isequal(T.Column2(i),'NIC')&isequal(T.Column2(i+1),'$')
cnicbefd=cnicbefd+1;
usernic=[usernic T.Column1(i)];
end
end
uniquenic=numel(unique(usernic));
12 个评论
ka chun yick
2022-5-12
Dyuman Joshi
2022-5-12
I have edited my answer
ka chun yick
2022-5-12
This maybe a stupid question. I have imported all the columns here, but it said Unrecognized function or variable "T" and Error on Untitled (line 4)
ka chun yick
2022-5-12
ka chun yick
2022-5-13
@Dyuman Joshi, apologise about that. I have deleted it. This is my second attampt. I have defined the T and here is the another error.
Dyuman Joshi
2022-5-13
Can you show what the values in T are?
ka chun yick
2022-5-13
Dyuman Joshi
2022-5-13
I saw that. But I don't know what is the data type. Can you post the data here so I can try it myself directly?
ka chun yick
2022-5-13
Dyuman Joshi
2022-5-13
编辑：Dyuman Joshi
2022-5-13
Okay, when you import T, what is the data type of Column 1 and 2? Char/string or categorical?
Asking because I am getting 2 different answers on based on method of importing.
ka chun yick
2022-5-13
Dyuman Joshi
2022-5-13
I have modified my code accordinly, please check.
ka chun yick
2022-5-13
0 个投票
Hi, i got the following error, it said 'countd' is unrecognized......
Unrecognized function or variable 'countd'.
Error in Untitled (line 6)
countd=countd+1; %number of '$' has been pressed.
4 个评论
Dyuman Joshi
2022-5-13
sorry, change cd=0 to countd=0.
ka chun yick
2022-5-14
@Dyuman Joshi okay, it seems got far more problems once changing it....
Index exceeds the number of array elements (10).
Error in categorical/subsref (line 21)
b.codes = a.codes(s.subs{:});
Error in tabular/dotParenReference (line 108)
b = b(rowIndices);
Error in Untitled (line 14)
if isequal(T.Column2(i),'NIC')&isequal(T.Column2(i+1),'$')
ka chun yick
2022-5-18
Dyuman Joshi
2022-5-18
This is just a data type mismatch in the if condition statement. Check what the data type in table T, then you can edit accorindingly as well.
ka chun yick
2022-5-19
0 个投票
@Dyuman Joshi. I am sure when i imported it from excel, it is a table as a whole. i have been reading some documents on how to converting type: https://uk.mathworks.com/help/matlab/data-type-conversion.html .But i still getting really confused on how to check the data and how to edit it from here, also the if condition statement..... Appologise for all the confusions......
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