This seemed like it should be very simple to do yet I've not been able to find an answer after weeks of looking.
I'm trying to remove strings that are no longer needed. Regex_replace sounds perfect but is not available in MySQL.
In MySQL how would I accomplish changing this:
[quote=ABC;xxxxxx]
to this:
[quote=ABC]
The issues are:
- this can appear anywhere in a text blob
- the xxxxxx can only be numeric but may be 6, 7 or 8 characters long
- not adding/removing any rows, just rewriting the contents of one column on one row at a time.
Thanks.
I don't think you really need REGEX_Replace (though it would make things easier of course).
Assuming that the example you presented is a real reflection of what you have:
Your starting point is with the string [quote=<something>;, meaning that you can start searching for [quote=,
Once you found it, you need to search for ; and after that for ],
Once you found them both, you know what to extract when where to start for the next search (if the pattern you mentioned can appear more than once within a singe blob.
Did I get you correctly?
EDIT
This paradigm is aimed to convert all instances of [quote=ABC;xxxxxx] to [quote=ABC] under the following assumptions:
The pattern can appear any number of times within the input string,
The length of xxxxxx is not fixed,
The resulting string (after removing all the appearances of ;xxxxxx) should replace the value in the table,
Performance is not an issue since either this is going to be a one-time job (through the whole table) or it will run every time on a single string (e.g. before INSERTing a new record).
Some MySQL functions that will be used:
INSTR: Searches within a string for the first appearance of a sub-string and returns the position (offset) where the sub-string was found,
SUBSTR: Returns a substring from a string (several ways to use it),
CONCAT: Concatenates two or more strings.
The guidelines presented here apply for the manipulation of a single INPUT string. If this needs to be used over, say, a whole table, simply get the strings into a CURSOR and loop.
Here are the steps:
Declare five INT local variables to serve as indices and total input string length, say L_Start, L_UpTo, l_Total_Length, l_temp1 and l_temp 2, setting the initial value for l_Start = 1 and l_Total_Length = LENGTH(INPUT_String),
Declare a string variable into which you will copy the "cleaned" result and initiate it as '', say l_Output_str; also declare a temporary string to hold the value of 'ABD', say l_Quote,
Start a infinite loop (you will set the exit condition within it; see below),
Exit loop if l_Start >= l_Total_Length (here is one of the two exit points from the loop),
Find the first location of '[quote=' within the input string starting from L_Start,
If the returned value is 0 (i.e. substring not found), concatenate the current contents of l_Output_str with whatever remains if the input string from position L_start (e.g. SET l_Output_str = CONCAT(l_Output_str,SUBSTR(INPUT_String,L_Start) ;) and exit loop (second exit position),
Search the input string for the ; symbol starting from L_start + 7 (i.e. the length of [quote=) and save the value in l_temp_1,
Search the input string for the ] symbol starting from L_start + 7 + l_temp2 and save the value in l_temp_2,
Add the found result to output string as SET l_Output_str = CONCAT(l_Output_str,'[quote=',SUBSTR(INPUT_String,L_Start + 7, l_temp_2 - l_temp_1),']') ;,
Set L_Start = L_Start + 7 + l_temp_2 + 1 ;
End of loop.
Notes:
As I neither made the code nor tested it, it is possible that I'm not setting indices correctly; you will need to perform detailed tests to make get it working as needed;
The above IS the method I suggested;
If the input string is very long (many MBs), you might observe poor performance (i.e. it might take few seconds to complete) because of the concatenations. There are some steps that can be taken to improve performance, but let's have this working first and then, if needed, tackle the performance issues.
Hope that the above is clear and comprehensive.
I am using a script in MatLab that works perfectly fine by itself, but I need to make a function out of it.
The script read a .csv file, extract all values, start a timer, and at each tick displays the corresponding coordinates extracted from the .csv, resulting in a 3D animation of my graph.
What I would like is to give it the location of the .csv, so that it starts displaying the graphs for this csv.
Here is what I have come up with:
function handFig(fileLoc)
csv=csvread(fileLoc,1,0);
both = csv(:,2:19);
ax=axes;
set(ax,'NextPlot','replacechildren');
Dt=0.1; %sampling period in secs
k=1;
hp1=text(both(k,1),both(k,2),both(k,3),'thumb'); %get handle to dot object
hold on;
hp2=text(both(k,4),both(k,5),both(k,6),'index');
hp3=text(both(k,7),both(k,8),both(k,9),'middle');
hp4=text(both(k,10),both(k,11),both(k,12),'ring');
hp5=text(both(k,13),both(k,14),both(k,15),'pinky');
hp6=text(both(k,16),both(k,17),both(k,18),'HAND');
L1=plot3([both(k,1),both(k,16)],[both(k,2),both(k,17)],[both(k,3),both(k,18)]);
L2=plot3([both(k,4),both(k,16)],[both(k,5),both(k,17)],[both(k,6),both(k,18)]);
L3=plot3([both(k,7),both(k,16)],[both(k,8),both(k,17)],[both(k,9),both(k,18)]);
L4=plot3([both(k,10),both(k,16)],[both(k,11),both(k,17)],[both(k,12),both(k,18)]);
L5=plot3([both(k,13),both(k,16)],[both(k,14),both(k,17)],[both(k,15),both(k,18)]);
hold off;
t1=timer('TimerFcn','k=doPlot(hp1,hp2,hp3,hp4,hp5,hp6,L1,L2,L3,L4,L5,both,t1,k)','Period', Dt,'ExecutionMode','fixedRate');
start(t1);
end
And the doplot function used:
function k=doPlot(hp1,hp2,hp3,hp4,hp5,hp6,L1,L2,L3,L4,L5,pos,t1,k)
k=k+1;
if k<5000%length(pos)
set(hp1,'pos',[pos(k,1),pos(k,2),pos(k,3)]);
axis([0 255 0 255 0 255]);
set(hp2,'pos',[pos(k,4),pos(k,5),pos(k,6)]);
set(hp3,'pos',[pos(k,7),pos(k,8),pos(k,9)]);
set(hp4,'pos',[pos(k,10),pos(k,11),pos(k,12)]);
set(hp5,'pos',[pos(k,13),pos(k,14),pos(k,15)]);
set(hp6,'pos',[pos(k,16),pos(k,17),pos(k,18)]);
set(L1,'XData',[pos(k,1),pos(k,16)],'YData',[pos(k,2),pos(k,17)],'ZData',[pos(k,3),pos(k,18)]);
set(L2,'XData',[pos(k,4),pos(k,16)],'YData',[pos(k,5),pos(k,17)],'ZData',[pos(k,6),pos(k,18)]);
set(L3,'XData',[pos(k,7),pos(k,16)],'YData',[pos(k,8),pos(k,17)],'ZData',[pos(k,9),pos(k,18)]);
set(L4,'XData',[pos(k,10),pos(k,16)],'YData',[pos(k,11),pos(k,17)],'ZData',[pos(k,12),pos(k,18)]);
set(L5,'XData',[pos(k,13),pos(k,16)],'YData',[pos(k,14),pos(k,17)],'ZData',[pos(k,15),pos(k,18)]);
else
k=1;
set(hp1,'pos',[pos(k,1),pos(k,2),pos(k,3)]);
axis([0 255 0 255 0 255]);
set(hp2,'pos',[pos(k,4),pos(k,5),pos(k,6)]);
set(hp3,'pos',[pos(k,7),pos(k,8),pos(k,9)]);
set(hp4,'pos',[pos(k,10),pos(k,11),pos(k,12)]);
set(hp5,'pos',[pos(k,13),pos(k,14),pos(k,15)]);
set(hp6,'pos',[pos(k,16),pos(k,17),pos(k,18)]);
end
However, when I run handFig('fileName.csv'), I obtain the same error everytime:
??? Error while evaluating TimerFcn for timer 'timer-7'
Invalid handle object.
I figured that it might come from the function trying to create a new 'csv' and 'both' everytime, so I tried removing them, and feeding the function the data directly, without results.
What is exactly the problem? Is there a solution?
Thanks a lot!
I think it's because when you call doPlot in the timer for the first time, you pass in t1 as an argument, and it might not exist the first time.
Does doPlot need t1 at all? I'd suggest modifying it so it's not used, and then your call to:
t1=timer('TimerFcn','k=doPlot(hp1,hp2,hp3,hp4,hp5,hp6,L1,L2,L3,L4,L5,both,k)','Period', Dt,'ExecutionMode','fixedRate');
Note the missing t1 in the doPlot call.
Either that, or initialise your t1 before you create the timer so it has some value to pass in.
Update (as an aside, can you use pause(Dct) in a loop instead? seems easier)
Actually, now I think it's a problem of scope.
It took a bit of digging to get to this, but looking at the Matlab documentation for function callbacks, it says:
When MATLAB evaluates function handles, the same variables are in scope as when the function handle was created. (In contrast, callbacks specified as strings are evaluated in the base workspace.)
You currently give your TimerFcn argument as a string, so k=doPlot(...) is evaluated in the base workspace. If you were to go to the matlab prompt, run handFig, and then type h1, you'd get an error because h1 is not available in the global workspace -- it's hidden inside handFig.
That's the problem you're running into.
However, the workaround is to specify your function as a function handle rather than a string (it says function handles are evaluated in the scope in which they are created, ie within handFig).
Function handles to TimerFcn have to have two arguments obj and event (see Creating Callback Functions). Also, that help file says you have to put doPlot in its own m-file to have it not evaluate in the base Matlab workspace.
In addition to these two required input arguments, your callback
function can accept application-specific arguments. To receive these
input arguments, you must use a cell array when specifying the name of
the function as the value of a callback property. For more
information, see Specifying the Value of Callback Function Properties.
It goes through an example of what you have to do to get this working. Something like:
% create timer
t = timer('Period', Dt,'ExecutionMode','fixedRate');
% attach `k` to t so it can be accessed within doPlot
set(t,'UserData',k);
% specify TimerFcn and its extra arguments:
t.TimerFcn = { #doPlot, hp1, hp2, hp3, ...., both };
start(t)
Note -- the reason k is set in UserData is because it needs to be somehow saved and modified between calls to doPlot.
Then modify your doPlot to have two arguments at the beginning (which aren't used), and not accept the k argument. To extract k you do get(timer_obj,'UserData') from within doPlot:
function k=doPlot(timer_obj, event, hp1,hp2,hp3,.....)
k = get(timer_obj,'UserData');
.... % rest of code here.
% save back k so it's changed for next time!
set(timer_obj,'UserData',k);
I think that's on the right track - play around with it. I'd highly recommend the mathworks forums for this sort of thing too, those people are whizzes.
This thread from the mathworks forum was what got me started and might prove helpful to you.
Good luck!