I have been trying to use =row(indirect("0-5000")) to work like I have read on all literature I could find and yet I keep getting the #REF error, which occurs when it processes the indirect(string) part of the formula. Is there a setting somewhere that is making my function to act improperly?
I am trying to produce an array of numbers inside a formula at time of calcution (so no stored array), based on a range of two numbers from 2 cells like the example 1/4 of the way down on https://exceljet.net/formula/create-array-of-numbers
Try,
=row(indirect("1:5000"))
There is no row 0 and a colon is used to delimit the upper and lower limits of a range.
Related
I'm trying to read amplitude from a waveform and shine a green, yellow or red light depending on the amplitude of the signal. I'm fairly new to labVIEW and couldnt get my idea that wouldve worked with any other programming language I know to work. What I'm trying to do is take the value of the signal and for everytime it updates I'll store the value of the amplitude into an index of a large array. With each measurement being stored in the n+1 index of the array.
After a certain amount of data points I want to start over and replace values in the array (I use the formula node with the modulus for this). By keeping a finite amount of indexes to check for max value I restrict my amplitude check to a certain time period.
However my problem is that whenever I use the replace array subset to insert a new value into index n, all the other index points get erased. Rendering it pretty much useless. I was thinking its the Initialize array causing problems but I just cant seem to wrap my head around what to do here.
I tried creating just basic arrays in the front panel, but those either are control or indicator arrays and can't seem to be both written and read from, its either control (read but not write) or indicate(write but not read)?. Maybe its just not possible to do what I had in mind in an eloquent way in LabVIEW. If its not possible to do this with arrays in LabVIEW I will look for a different way to do it.
I'm pretty sure I got most of the rest of the code down except for an unfinished part here and there. Its just my issue with the arrays not working as I want them too.
I expected the array to retain its previously inputted data for index n-1 when index n is inputted. And only to be replaced once the index has come back to that specific point.
Instead its like a new array is initialized every time a new index is input.
download link for the VI
What you want to do:
Transport the content of the modified array into the next iteration of the WHILE loop.
What happens:
On each iteration, the content of the array is the same. It is the content of the initial array you created outside.
To solve this, right-click the orange square on the left border of the loop, and make it a "shift register". The symbol changes, and a similar symbol appears on the right border. Now, wire the modified array to the symbol on the right. What flows out into that symbol on the right, comes in from the left symbol on the next iteration.
Edit:
I have optimized your code a little. There is a modulo function, and an IF clause can handle ranges. ..3 means "values lower or equal 3". The next case is "Default", the next "7..". Unfortunately, this only works for integers. Otherwise, one would use nested IF clauses with the < comparator or similar.
So I'm having difficulties understanding fully how arrays works and when they are used by excel and specifically what happens in the background.
From reading the past few hours I understand that one of the reasons my Index Match doesn't work without array is simply because its a multicriteria Match that I use as below:
{=INDEX(D30:E36,MATCH(F33&G33,B30:B36&C30:C36),2)}
From what I understand the reason is that Match returns a {x,y} result which classifies it as an array formula. But considering the point is to get a row number, if the row I'm looking for is 5 then Match will return a {5,5} for row number for Index. And then Index interprets this as just 5? or what exactly happens in the background here?
Then I found an article which showed how to circumvent the array formula and not need ctrl+shift+enter as shown below. How does the below change things and what happens in the background?
=INDEX(D30:E36,MATCH(F33&G33,INDEX(B30:B36&C30:C36)),2)
The below is a an array SUM/COUNTIF formula which counts unique cells only which does not work without array brackets. Why is that and how does it work? It involves maths so I'm not sure.
{=SUM(1/(COUNTIF(A1:A5,A1:A5)))}
Thank you!
I am struggling with an array formula, that logically seems sound, however it doesn't appear to be working correctly. I have been working on a complex sheet, that is not to include VBA, which has made it formula heavy, and using arrays instead.
In the image below, the first part is the problem, for the data shown in columns A-F, I wish to get a sum of the values that match the values in I1:K1.
The formula I have used to begin with can be seen in the first image also, this evaluates, pressing F9, to give me the desired output 20,40 & 50. However when I add the SUM around the formula, I only get the first result out.
I think this is an issue with me not seeing the wood for the trees on this one.
Thanks in advance.
This array formula seems to work:
=SUM((IFERROR(MATCH(A1:F1,I1:K1,0),0)>0)*A2:F2)
There are probably multiple better formulas to achieve the same thing.
But to talk about why this fails:
It is because of the OFFSET function returns a reference rather than a value. And so used in this array formula it returns an array of references {B2,D2,E2} instead of an array of values {20,40,50} which leads to the problem.
If you are using:
=SUMPRODUCT(OFFSET(A2,0,MATCH($I$1:$K$1,$A$1:$F$1,0)-1))
then using Evaluate Formula, you will get:
SUMPRODUCT({#VALUE,#VALUE,#VALUE})
in next to last step and 0 as the result. So the OFFSET leads to error values because of it returns an array of references which will not be dereferenced automatically and so will become #VALUE error each.
If you are using
=SUMPRODUCT(N(OFFSET(A2,0,MATCH($I$1:$K$1,$A$1:$F$1,0)-1)))
then it works and returns 110. So the N dereferences the references of each OFFSET and so the whole formula leads to an array of values {20,40,50} in sum.
{=SUM(N(OFFSET(A2,0,MATCH($I$1:$K$1,$A$1:$F$1,0)-1)))}
works too.
These problems occur using funktions like OFFSET and INDIRECT, which returns references rather than values, in array formulas. And having a dereferencing function around the OFFSET or INDIRECT stops the problems.
It is the same with:
=SUMPRODUCT(INDIRECT("R2C"&MATCH(I1:K1,A1:F1,0),FALSE))
versus
=SUMPRODUCT(N(INDIRECT("R2C"&MATCH(I1:K1,A1:F1,0),FALSE)))
I am interested in spreadsheet functions, not VBA solutions, to be included in a single cell formula.
[A1:A15 contain numeric values from 1 to 127, B1:B15 contain integers from 1 to 7 that set a divisor.]
Given the function:
=SUMPRODUCT(MOD(FREQUENCY(A1:A15;A1:A15);B1:B15))
FREQUENCY(A1:A15;A1:A15) gives a 1-column array of 15+1 rows, whereas the second part (B1:B15) is a 1-column array of 15 rows.
I would like to change the resulting array given by FREQUENCY (only in memory -not explicit in sheet-) from a 1-column 16 rows array to a 1-column 15 rows array with the first 15 cell values of that array.
[FREQUENCY documentation: https://support.office.com/en-us/article/FREQUENCY-function-44e3be2b-eca0-42cd-a3f7-fd9ea898fdb9 NB: for Excel, second remark states number of elements that depend on bins_array. ]
I would appreciate suggestions.
Thus, both arrays within MOD will have the same dimensions and SUMPRODUCT will not find cells with error values. I can disregard error values using IF and ISERROR within SUMPRODUCT, but I'd rather disregard the non-relevant part of the FREQUENCY resulting array if it is possible.
It has been thought that making it more specific might be more helpful, so it has been heavily reduced and simplified.
With external help, I have been able to fine-tune a way to solve my problem using INDEX in array formula mode. I am posting the answer in case it helps others.
One way: Put FREQUENCY(A1:A15;A1:A15), or any formula that produces an multi-cell array, within INDEX and have 2nd and/or 3rd arguments as array of consecutive values which will represent rows/columns.
INDEX(FREQUENCY(A1:A15;A1:A15);ROW(INDIRECT("1:" & ROWS(FREQUENCY(A1:A15;A1:A15)-1));1)
First argument within INDEX is the resulting array coming from a formula to shrink (from 16x1 to 15x1), which would be a multi-cell array formula if explicitly entered; second argument is the array 1..15 given by row numbers from 1 to the number of total rows of the "array from formula to shrink" MINUS 1: the first 15 (out of 16) values in the array from a formula; 3rd argument is the column of the shrank array (if need be, more than one could be selected using an analogue to the second argument).
In the particular case of FREQUENCY, because it is known that we are interested in the "bins" part of the function, the formula can be simplified by including the total rows of the "bins"/"intervals" array inside FREQUENCY (its second argument). We will have
INDEX(FREQUENCY(A1:A15;A1:A15);ROW(INDIRECT("1:" & ROWS(A1:A15)));1)
and the complete formula would become
SUMPRODUCT(MOD(INDEX(FREQUENCY(A1:A15;A1:A15);ROW(INDIRECT("1:" & ROWS(A1:A15)));1);B1:B15))
Now, both dividend and divisor of MOD have exactly the same dimensions (15x1) and because B1:B15 includes integers greater than 0 there are no errors.
Thanks all for helping me in making question more concise and better formatted.
ADDITIONAL INFORMATION: As pointed out correctly in comments by XOR LX, this does not seem to work in the widely popular spreadsheet software Excel. It has been developed for an INDEX function inside SUMPRODUCT as used in Open Office Calc which I had mistakenly thought 100% equivalent to Excel's version. A more complete answer perhaps using other functions would be appreciated.
In the previous answer, XOR LX points out very correctly that this formula cannot work in Excel, due to row_num/column_num argument behaviour. Very kindly XOR LX has shown me how that approach can work, and also thanks and credit for supplying a good answer: "INDEX can be used to redimension array (even dynamically created ones) if the row_num/column_num array is coerced to take an arbitrary array with the right dimensions, as shown on this blog entry " The following formula has been checked in Excel 2010 and has the expected results:
SUMPRODUCT(MOD(INDEX(FREQUENCY(A1:A15,A1:A15),N(INDEX(ROW(INDIRECT("1:" & ROWS(A1:A15))),,)),1),B1:B15))
NB: row_num argument of first INDEX, a ROW generated auxiliary array, has been nested inside N(INDEX([...],,)); at least one comma is necessary to account for the two arguments minimum of the nested INDEX. It is in itself interesting the discussion that applies generally to INDEX's arguments, and other functions', that need to be coerced to take arrays (see, here and here at XOR LX's blog). For Open Office users it might be worth stressing the point made at the blog
Unlike OFFSET, (...) for which the first parameter must be a
reference (...) in the worksheet, INDEX can also accept –
and manipulate – for its reference arrays which consist of values
generated e.g. via other subfunctions within the formula. XOR LX's blog
That would be indeed the case in changing the dimension in an array as in this question, but also useful in reversing or displacing the values in an array, for example. Open Office accepts arrays as row_num/column_num, so the coercion is not needed and some formulas rely on this, but without it, these formulas are unlikely to work when files are open in Excel.
Regrettably, this type of coercion is not passed correctly to Open Office, and formula need to be "decoerced" to work, at least in my casual tests.
In order to use a formula that would work in both spreadsheet programs regarding shortening arrays, the only thing I have managed is the following (required: arrays must be single-column)
SUMPRODUCT(
(COLUMN(INDIRECT("R1C1:R"& ROWS(vals_to_mod) &"C"& ROWS(FREQUENCY(vals_for_freq,vals_for_freq)),FALSE))
-ROW(COLUMN(INDIRECT("R1C1:R"& ROWS(vals_to_mod) &"C"& ROWS(FREQUENCY(vals_for_freq,vals_for_freq)),FALSE))
=0)
*MOD(TRANSPOSE(FREQUENCY(vals_for_freq,vals_for_freq)),vals_to_mod)
)
(it "shortens" one array to the shortest of the pair, by creating an auxiliary array with TRUE/1s on the diagonal starting top-left and FALSE/0s elsewhere, therefore disregarding all defined values outside the square section of the array. Thus, SUMPRODUCT adds values within the diagonal of the square section which are the product of the corresponding values up to the last value of the shorter array.)
I have been given an assignment to write a program that reads in a number of assignment marks from a text file into an array, and then counts how many marks there are within particular brackets, i.e. 40-49, 50-59 etc. A value of -1 in the text file means that the assignment was not handed in, and a value of 0 means that the assignment was so bad that it was ungraded.
I could do this easily using a couple of for loops, and then using if statements to check the values whilst incrementing appropriate integers to count the number of occurences, but in order to get higher marks I need to implement the program in a "better" way. What would be a better, more efficient way to do this? I'm not looking for code right now, just simply "This is what you should do". I've tried to think of different ways to do it, but none of them seem to be better, and I feel as if I'm just trying to make it complicated for the sake of it.
I tried using the 2D array that the values are stored in as a parameter of a function, and then using the function to print out the number of occurences of the particular values, but I couldn't get this to compile as my syntax was wrong for using a 2D array as a parameter, and I'm not too sure about how to do this.
Any help would be appreciated, thanks.
Why do you need a couple for loops? one is enough.
Create an array of size 10 where array[0] is marks between 0-9, array[1] is marks between 10-19, etc. When you see a number, put it in the appropriate array bucket using integer division, e.g. array[(int)mark/10]++. when you finish the array will contain the count of the number of marks in each bucket.
As food for thought, if this is a school assignment, you might want to apply other things you have learned in the course.
Did you learn sorting yet? Maybe you could sort the list first so that you are not iterating over the array several times. You can just go over it once, grab all the -1's, and spit out how many you have, then grab all the ones in the next bracket and so on.
edit: that is of course, assuming that you are using a 1d array.