I've got an array declaration which results in 144 slots.
I don't understand how I've got to this number. Also, what means all those commas between numbers?
Dim arr4(1, 5, 5, 0 To 1) As Long
Debug.Print ArraySize(arr4)
The , denotes a new dimension. So arr4 has 4 dimensions.
When using 0 to 1 it is saying that the fourth dimension has two, 0 and 1
When using just one number 5 then the starting point is assumed 0 unless changed in the settings, so there are 6 in that dimension: 0,1,2,3,4,5
The reason there are 144 is because 2*6*6*2=144
Think of it this way.
1st dimension is rows with two row (0,1)
2nd dimension is columns with 6 columns (0,1,2,3,4,5)
3rd dimension create 6 sheets of the above configuration (0,1,2,3,4,5)
4th dimension create 2 workbooks with each having 6 sheets with 12 cells (0,1)
Thus there is 144 cells in which to put data.
Related
I have been trying to find an answer online but haven't been able to find one.
When given a range of values, selecting this range and dragging out the cells will generate more values. How are these values calculated? In certain cases it is easy to figure, like when all values are the same or when they are increasing by a steady interval, but how are values calculated when more random sequences of values are given?
For example, given the range
Val 1
Val 2
Val 3
Val 4
Val 5
Val 6
5
5
6
54
5
2
when selecting all values and dragging out to the right, I will end up with the following range:
Val 1
Val 2
Val 3
Val 4
Val 5
Val 6
Dragged out 1
Dragged out 2
Dragged out 3
5
5
6
54
5
2
16.133
17.976
18.019
How are the three dragged out values calculated?
This is done using linear regression, as calculated by the least squares method, explained in this Wikipedia-article.
As an illustration, I have created an Excel sheet, containing the numbers from 1 to 6 and I've added your numbers. Then I've added the numbers 7-9 and used least squares method (as supported by Excel) and put everything in a graph. Please realise that the original values are shown but overwritten by the estimated values in the attached graph (the yellow cells contain the formula of the cell at its left):
Please forgive any errors or shortcomings in this question, it's my first on stackoverflow.
I have two sets of data in Excel of differing lengths and frequency, and would like to be able to place a value of 0 for where they don't synchronise, and match the rest.
For example, dataset 1 could be:
Date Set1
01-01-2010 10
01-03-2010 4
01-04-2010 8
01-05-2010 5
01-06-2010 10
01-09-2010 12
01-10-2010 9
01-11-2010 4
And dataset 2 could be:
Date Set2
01-03-2010 102
01-06-2010 104
01-10-2010 102
I'm looking for an output table that displays the values alongside each other for dates matching, 0 otherwise, like so:
Date Set1 Set2
01-01-2010 10 0
01-03-2010 4 102
01-04-2010 8 0
01-05-2010 5 0
01-06-2010 10 104
01-09-2010 12 0
01-10-2010 9 102
01-11-2010 4 0
I can't seem to be able to crack this with my limited knowledge and the lack of synchronisation in the data. Any help would be much appreciated, thanks.
You can do this using a VLOOKUP nested in an IFERROR statement.
The two equations used (and dragged down to last unique date row) are:
H3 = IFERROR(VLOOKUP(G3,A:B,2,0),0)) & I3 = IFERROR(VLOOKUP(G3,D:E,2,0),0))
This will not work if you have duplicate dates in the same data set with varying values since VLOOKUP will always return the first matched value (reading top down).
Place Set1 in A1:B9 (header in row 1). Add a column of zeros next to it in column C, so A2:A9 is dates, B2:B9 is values and C2:C9 is zeros.
Place Set2 (without the header) in A10:B12; move the Set2 data to column C and put zeros in column B, so A10:A12 is dates, B10:B12 is zeros, C10:C12 is values.
Sort the range A2:C12 by Date (column A).
Easier to show with a screenshot but newbies are not allowed to post images.
I'm facing an issue with the use of Redim in VBA of MS Excel in a 3D array. How can I append a new array with different dimension than the first one to the first array and then another one and then ...; and then be able to read a specific group of data from this newly created matrix (array) with different number of columns in each row, for example, the 2nd group of data. Here is an example to clarify the matter.
Arr1 is in 3x3
Arr2 is in 5x5
Arr3 is in 7x7
Arr4 is in 9x9
Arr5 is in 11x11 dimensions.
Now if I append them together the resulting matrix should be in this format - for example:
1 2 3
4 5 6
7 8 9
1 2 3 4 5
6 7 8 9 1
2 3 4 5 6
7 8 9 1 2
3 4 5 6 7
...
...
1 2 3 ... 11
1 2 3 ... 11
(another 8 rows)
1 2 3 ... 11
(total of 11 rows)
Next I want to be able to read a group of data (sub-matrix) from the resulting matrix, for example the 2nd group of data, which is in 5x5.
If I use Redim in between each loop, while appending those new group of arrays and so to adjust the dimensions of the first matrix and continuing to do so, the last dimension will be in 11x11, which does not give me the needed dimension; in this case 5x5.
I was wondering, if there is any recommendation you could kindly provide. Thank you.
I am working at moving my data over from Excel to Matlab. I have some data that I want to average based on multiple criteria. I can accomplish this by looping, but want to do it with matrix operations only, if possible.
Thus far, I have managed to do so with a single criterion, using accumarray as follows:
data=[
1 3
1 3
1 3
2 3
2 6
2 9];
accumarray(data(:,1),data(:,2))./accumarray(data(:,1),1);
Which returns:
3
6
Corresponding to the averages of items 1 and 2, respectively. I have at least three other columns that I need to include in this averaging but don't know how I can add that in. Any help is much appreciated.
For your single column, you don't need to call accumarray twice, you can provide a function handle to mean as the fourth input
mu = accumarray(data(:,1), data(:,2), [], #mean);
For multiple columns, you can use the row indices as the second input to accumarray and then use those from within the anonymous function to access the rows of your data to operate on.
data = [1 3 5
1 3 10
1 3 8
2 3 7
2 6 9
2 9 12];
tmp = accumarray(data(:,1), 1:size(data, 1), [], #(rows){mean(data(rows,2:end), 1)});
means = cat(1, tmp{:});
% 3.0000 7.6667
% 6.0000 9.3333
I am trying to find the equation of a plane of best fit to a set of x,y,z data using the LINEST function. Some of the z data is missing, meaning that there are #N/As in the z column. For example:
A B C
(x) (y) (z)
1 1 1 5.1
2 2 1 5.4
3 3 1 5.7
4 1 2 #N/A
5 2 2 5.2
6 3 2 5.5
7 1 3 4.7
8 2 3 5
9 3 3 5.3
I would like to do =LINEST(C1:C9,A1:B9), but the #N/A causes this to return a value error.
I found a solution for a single independent variable (one column of known_x's, i.e. fitting a line to x,y data), but I have not been able to extend it for two independent variables (two known_x's columns, i.e. fitting a plane to x,y,z data). The solution I found is here: http://www.excelforum.com/excel-general/647448-linest-question.html, and the formula (slightly modified for my application) is:
=LINEST(
N(OFFSET(C1:C9,SMALL(IF(ISNUMBER(C1:C9),ROW(C1:C9)-ROW(C1)),
ROW(INDIRECT("1:"&COUNT(C1:C9)))),0,1)),
N(OFFSET(A1:A9,SMALL(IF(ISNUMBER(C1:C9),ROW(C1:C9)-ROW(C1)),
ROW(INDIRECT("1:"&COUNT(C1:C9)))),0,1)),
)
which is equivalent to =LINEST(C1:C9,A1:A9), ignoring the row containing the #N/A.
The formula from the posted link could probably be adapted but it is unwieldy. Least squares with missing data can be viewed as a regression with weight 1 for numeric values and weight 0 for non-numeric values. Based on this observation you could try this (with Ctrl+Shift+Enter in a 1x3 range):
=LINEST(IF(ISNUMBER(C1:C9),C1:C9,),IF(ISNUMBER(C1:C9),CHOOSE({1,2,3},1,A1:A9,B1:B9),),)
This gives the equation of the plane as z=-0.2x+0.3y+5 which can be checked against the results of using LINEST(C1:C8,A1:B8) with the error row removed.