I am trying to realize my idea in matlab.
I consider two column A and B.
A=data(:,1)
B=data(:,5)
the data look like:
A B
1 1
2 1
3 1
... ...
100 20
... ...
150 30
151 1
... ...
The values in column A are timepoints.
I start with the first element in column A. It schould be A(1,1) and look on the first element in the column B B(1,1). If B(1,1)==1its true,if not its false. Then I increase consider the second raw of the column A and second raw of the column B and so on until the last raw of A and B.
How can I construck this loop??
You can just consider B likes the following:
result = (B == 1);
The result would be the same size of B such as you want. Nowm you can get the value of A on result likes the following:
valid_times = A(result);
Related
I'am trying to use this formula to make it work
=ARRAYFORMULA(IF(ISDATE_STRICT(S2:S) ; (MATCH(MAX(AB2:AB),AB2:AB;0)-1) ; "" ))
If there is a date in Column "S" I want it to display the sum of the blanks that would appear if in Column "S" is text
=ARRAYFORMULA(IF(ISDATE_STRICT(S2:S) ; ArrayFormula(MATCH(FALSE ; ISBLANK(AB2:AB) ; 0)-1) ; "" ))
I've tried this one as well but I only get 0's as a result.
Any idea how I can make it work?
Here is the sample sheet.
https://docs.google.com/spreadsheets/d/19f5phXeAwXwrKbWz7njgbznmurOav72GUuo_5IGcbls/edit?usp=sharing
in Q2 use:
=ARRAYFORMULA(IF(ISBLANK(
I1:INDEX(I:I; ROWS(I:I)-1));
{N2:INDEX(N:N; ROWS(N:N))\
I1:INDEX(N:N; ROWS(N:N)-1)};
I1:INDEX(O:O; ROWS(O:O)-1)))
in X2 use:
=INDEX(LAMBDA(x; IFNA(VLOOKUP(x; QUERY(VLOOKUP(ROW(x);
IF(ISDATE_STRICT(x); {ROW(x)\x}); 2; 1);
"select Col1,count(Col1) group by Col1"); 2; 0)-1))
(Q2:INDEX(Q:Q; MAX((Q:Q<>"")*ROW(Q:Q)))))
UPDATE:
we start with column Q. we can take a range Q2:Q but that range contains a lot of empty rows. the next best thing is to check the last non-empty row and set it as the end of the range resulting in Q2:Q73. but static 73 won't do in case the dataset would grow or shrink so to get 73 dynamically we take the MAX of multiplication of Q:Q not being empty and row number of that case eg. Q:Q<>"" will output only TRUE or FALSE so what we are getting is
...
TRUE * 72 = 1 * 72 = 72
TRUE * 73 = 1 * 73 = 73
FALSE * 74 = 0 * 74 = 0
...
so the formula for getting Q2:Q73 is:
=Q2:INDEX(Q:Q; MAX((Q:Q<>"")*ROW(Q:Q)))
it could also be:
=INDEX(INDIRECT("Q2:Q"&MAX((Q:Q<>"")*ROW(Q:Q))))
but it's just long to type... next, we use the new LAMBDA function that allows us to reference cell/range/formula with a placeholder. simple LAMBDA syntax is:
=LAMBDA(x; x)(A1)
where x is A1 and we can do whatever we want with the 2nd (x) argument of LAMBDA like for example:
=LAMBDA(a, a+a*120-a/a)(A1)
you can think of it as:
LAMBDA(A1, A1+A1*120-A1/A1)(A1)
or as just:
=A1+A1*120-A1/A1
the issue here is that we repeat A1 4 times but with LAMBDA we do it only once. also, imagine if we would have 100 characters long formula instead of A1 so the final formula with lambda would be 300 characters shorter compared to "old way" formula.
back to our formula... x is the representation of Q2:Q73. now let's focus on VLOOKUP. basically, the idea here is that IF Q column contains a date we return that date, otherwise we return the last date from above. simply put:
=ARRAYFORMULA(VLOOKUP(ROW(Q2:Q73);
IF(ISDATE_STRICT(Q2:Q73); {ROW(Q2:Q73)\Q2:Q73}); 2; 1))
as you can see Y2, Y3 and Y4 are the same so all we need to do is to count them up and later take away one to exclude Q2 but include just Q3 and Q4 eg. 3-1=2. for that we use simple QUERY where the output is:
date count
30.06.2022 3
so all we need to do is to pair up dates from Q column to QUERY output for that we use the outer VLOOKUP where the output is as follows:
3
#N/A
#N/A
9
#N/A
#N/A
...
now is the right time for that -1 correction while we have these errors coz ERROR-1=ERROR and 3-1=2 so after this -1 correction the output is:
2
#N/A
#N/A
8
#N/A
#N/A
...
and all we need to do now is to hide errors with IFERROR and the output is column X
I have a table
t:([]a:`a`b`c;b:1 2 3;c:`x`y`z)
I would like to iterate and process each row.
The thing is that the processing logic for each row may result in arbitrary lines of data, after the full iteration the result maybe as such e.g.
results:([]a:`a1`b1`b2`b3`c1`c2;x:1 2 2 2 3 3)
I have the following idea so far but doesn't seem to work:
uj { // some processing function } each t
But how does one return arbitrary number of data append the results into a new table?
Assuming you are using something from the table entries to indicate your arbitrary value, you can use a dictionary to indicate a number (or a function) which can be used to apply these values.
In this example, I use the c column of the original table to indicate the number of rows to return (and the number from 1 to count to).
As each entry of the table is a dictionary, I can index using the column names to get the values and build a new table.
I also use raze to join each of the results together, as they will each have the same schema.
raze {[x]
d:`x`y`z!1 3 2;
([]a:((),`$string[x[`a]],/:string 1+til d[x[`c]]);x:((),d[x[`c]])#x[`b])
} each t
Not sure if this is what you want, but you can try something like this:
ungroup select a:`${y,/:x}[string b]'[string a],b from t
Or you can use accumulators if you need the result of the previous row calculations like this:
{y[`b]+:last[x]`b;x,y}/[t;t]
If your processing function is outputting tables that conform, just raze should suffice:
raze {y#enlist x}'[t;1 3 2]
a b c
-----
a 1 x
b 2 y
b 2 y
b 2 y
c 3 z
c 3 z
Otherwise use (uj/)
(uj/) {y#enlist x}'[t;1 3 2]
a b c
-----
a 1 x
b 2 y
b 2 y
b 2 y
c 3 z
c 3 z
Your best answer will depend very much on how you want to use the results computed from each row of t. It might suit you to normalise t; it might not. The key point here:
A table cell can be any q data structure.
The minimum you can do in this regard is to store the result of your processing function in a new column.
Below, an arbitrary binary function f returns its result as a dictionary.
q)f:{n:1+rand 3;(`$string[x],/:"123" til n)!n#y}
q)f [`a;2]
a1| 2
a2| 2
q)update d:a f'b from t
a b c d
---------------------
a 1 x `a1`a2`a3!1 1 1
b 2 y (,`b1)!,2
c 3 z `c1`c2!3 3
But its result could be any q data structure.
You were considering a unary processing function:
q)pf:{#[x;`d;:;] f . x`a`b}
q)pf each t
a b c d
---------------------
a 1 x `a1`a2`a3!1 1 1
b 2 y `b1`b2!2 2
c 3 z `c1`c2`c3!3 3 3
You might find other suggestions at KX Community.
If I understand correctly your question you need something like this :
(uj/){}each t
Check this bit :
(uj/)enlist[t],{x:update x:i from?[rand[20]#enlist x;();0b;{x!x}rand[4]#cols[x]];{(x;![x;();0b;(enlist`a)!enlist($;enlist`;((';{raze string(x;y)});`a;`i))])[y~`a]}/[x;cols x]}each t
This part :
x:update x:i from
// functional form of a function that takes random rows/columns
?[rand[20]#enlist x;();0b;{x!x}rand[4]#cols[x]];
// some for of if-else and an update to generate column a (not bullet proof)
{(x;![x;();0b;(enlist`a)!enlist($;enlist`;((';{raze string(x;y)});`a;`i))])[y~`a]}/[x;cols x]
Basically the above gives something like :
q){x:update x:i from?[rand[20]#enlist x;();0b;{x!x}rand[4]#cols[x]];{(x;![x;();0b;(enlist`a)!enlist($;enlist`;((';{raze string(x;y)});`a;`i))])[y~`a]}/[x;cols x]}each t
+`a`b`c`x!(`a0`a1`a2`a3`a4`a5`a6`a7;1 1 1 1 1 1 1 1;`x`x`x`x`x`x`x`x;0 1 2 3 ..
+`a`x!(`a0`a1`a2`a3`a4`a5;0 1 2 3 4 5)
+`a`b`c`x!(`a0`a1`a2;1 1 1;`x`x`x;0 1 2)
+`a`b`c`x!(`a0`a1`a2`a3`a4`a5`a6`a7`a8`a9`a10`a11;1 1 1 1 1 1 1 1 1 1 1 1;`x`..
or taking the first one :
q)first{x:update x:i from?[rand[20]#enlist x;();0b;{x!x}rand[4]#cols[x]];{(x;![x;();0b;(enlist`a)!enlist($;enlist`;((';{raze string(x;y)});`a;`i))])[y~`a]}/[x;cols x]}each t
a b x
--------
a0 1 0
a1 1 1
a2 1 2
a3 1 3
a4 1 4
a5 1 5
a6 1 6
a7 1 7
a8 1 8
a9 1 9
a10 1 10
You can do
(uj/)enist[t],{ // some function }each t
to get what you want. Drop the enlist[t] if you don't want the table you start with in your result
Hope this helps.
I have a 29736 x 6 table, which is referred to as table_fault_test_data. It has 6 columns, with names wind_direction, wind_speed, air_temperature, air_pressure, density_hubheight and Fault_Condition respectively. What I want to do is to label the data in the Fault_Condition (last table column with either a 1 or a 0 value, depending on the values in the other columns.
I would like to do the following checks (For eg.)
If wind_direction value(column_1) is below 0.0040 and above 359.9940, label 6 th column entry corresponding to the respective row of the table as a 1, else label as 0.
Do this for the entire table. Similarly, do this check for others
like air_temperature, air_pressure and so on. I know that if-else
will be used for these checks. But, I am really confused as to how I
can do this for the whole table and add the corresponding value to
the 6 th column (Maybe using a loop or something).
Any help in this
regard would be highly appreciated. Many Thanks!
EDIT:
Further clarification: I have a 29736 x 6 table named table_fault_test_data . I want to add values to the 6 th column of table based on conditions as below:-
for i = 1:29736 % Iterating over the whole table row by row
if(1st column value <x | 1st column value > y)
% Add 0 to the Corresponding element of 6 th column i.e. table_fault_test_data(i,6)
elseif (2nd column value <x | 2nd column value > y)
% Add 0 to the Corresponding element of 6 th column i.e. table_fault_test_data(i,6)
elseif ... do this for other cases as well
else
% Add 1 to the Corresponding element of 6 th column i.e. table_fault_test_data(i,6)
This is the essence of my requirements. I hope this helps in understanding the question better.
You can use logical indexing, which is supported also for tables (for loops should be avoided, if possible). For example, suppose you want to implement the first condition, and also suppose your x and y are known; also, let us assume your table is called t
logicalIndecesFirstCondition = t{:,1} < x | t{:,2} >y
and then you could refer to the rows which verify this condition using logical indexing (please refer to logical indexing
E.g.:
t{logicalIndecesFirstCondition , 6} = t{logicalIndecesFirstCondition , 6} + 1.0;
This would add 1.0 to the 6th column, for the rows for which the logical condition is true
What I have is a variable X which has values assigned to it in the form of a table of 9 columns and around 100 rows. Here is an example:
X =
Columns 1 through 7
-2.2869 -1.1168 0.1430 -4.0753 1.7620 -6.3229 -3.1997
-2.2504 -1.1022 0.2046 -3.9865 1.7423 -6.2172 -3.1231
-2.2138 -1.0876 0.2663 -3.8977 1.7226 -6.1115 -3.0465
-2.1772 -1.0730 0.3279 -3.8089 1.7029 -6.0058 -2.9700
I need to create a for loop that extracts the first r rows of the first 'p' colmuns. For example r=3 and p=4.
Any idea on how I can do that?
I suggest you don't use a for-loop, but rather index directly into the matrix:
out = X(1:r,1:p)
returns the first r rows and p columns of X.
So, presume a matrix like so:
20 2
20 2
30 2
30 1
40 1
40 1
I want to count the number of times 1 occurs for each unique value of column 1. I could do this the long way by [sum(x(1:2,2)==1)] for each value, but I think this would be the perfect use for the UNIQUE function. How could I fix it so that I could get an output like this:
20 0
30 1
40 2
Sorry if the solution seems obvious, my grasp of loops is very poor.
Indeed unique is a good option:
u=unique(x(:,1))
res=arrayfun(#(y)length(x(x(:,1)==y & x(:,2)==1)),u)
Taking apart that last line:
arrayfun(fun,array) applies fun to each element in the array, and puts it in a new array, which it returns.
This function is the function #(y)length(x(x(:,1)==y & x(:,2)==1)) which finds the length of the portion of x where the condition x(:,1)==y & x(:,2)==1) holds (called logical indexing). So for each of the unique elements, it finds the row in X where the first is the unique element, and the second is one.
Try this (as specified in this answer):
>>> [c,~,d] = unique(a(a(:,2)==1))
c =
30
40
d =
1
3
>>> counts = accumarray(d(:),1,[],#sum)
counts =
1
2
>>> res = [c,counts]
Consider you have an array of various integers in 'array'
the tabulate function will sort the unique values and count the occurances.
table = tabulate(array)
look for your unique counts in col 2 of table.