In an xquery expression, I have obtained a set of values within a for-expression, and one value is in a separate variable.
Now, I want to subtract the single value from first value of the list, and then subtract consecutive members of the list from each other-- and in the resulting set of difference values, I want to obtain the min/max values...
The query upto now looks like this--
let $value1:= 1998
let $rows_citations:=
$doc//div[#id="patent_citations"]
/div[#id="patent_citations_v"]
/table[#class="rel_patent"]
/tbody/tr[1]
/following-sibling::tr
for $pos in $rows_citations/position()
let $date2_c := customfn:dateconverter1($rows_citations[$pos]/td[3])
Now the subtraction I want is between first value of date2_c and value 1, and after that between consecutive members of date2_c... And from the resulting list I want the min/max values... How do I go about doing this?
I am esp. confused about creating a new list variable that stores all the differences, esp. when we are already inside a for loop, and are iterating over each value of a list (via variable date2_c)
I. This XQuery 3.0 query (which is also a pure XPath 3.0 expression):
let $pVal := 1,
$vList := (2,4,7,11,16),
$vList2 := ($pVal, subsequence($vList, 1, count($vList)-1)),
$vSubtactedList :=
map-pairs(function($m as xs:integer, $n as xs:integer) as xs:integer
{
$m - $n
},
$vList,
$vList2
)
return
(min($vSubtactedList), max($vSubtactedList))
produces the wanted result the minimum and maximum values from the list of subtractions:
1 5
II. XQuery 1.0 solution:
let $pVal := 1,
$vList := (2,4,7,11,16),
$vList2 := ($pVal, subsequence($vList, 1, count($vList)-1)),
$vSubtactedList :=
for $i in 1 to count($vList)
return
$vList[$i] - $vList2[$i]
return
(min($vSubtactedList), max($vSubtactedList))
This again produces the same correct result:
1 5
Related
I want to use the resulting median as the parameter for calculating "larger". How can I do this?
{
"h": {
"data":
[1,3,5,2,6,8,4,23,7,3]
}
}
jsonata expression:
[{
"median" : $sort(h.data)[5],
"larger" : h.data.($ > 5)
}]
https://try.jsonata.org/1x8emp3oK
Solution - The key you're missing is the usage of variables. Also, the median of your set is 4.5, not 5 because the count of values is even, so the median becomes an average of two middle numbers.
In my solution, I calculate median, assign it to a variable using $variable_name := <calculation> syntax, and refer to that result further in the array filtering.
Keep in mind that if you're using variables, whole expression must be wrapped in parenthesis ( ... ).
I have a seemingly simple issue with my understanding of map types in Go. If I create a simple map such as
var thisMap = map[string]string {
"8f14e45fceea167a5a36dedd4bea2543": "Charming",
"1679091c5a880faf6fb5e6087eb1b2dc": "Citi",
"e4da3b7fbbce2345d7772b0674a318d5": "Chase",
}
Populate the keys into an array
keys := make([]string, len(supportedCards))
for k := range supportedCards {
keys = append(keys, k)
}
Then try to join these keys into a comma separated value that I can append to any string
fmt.Println(strings.Join(keys,","))
I expect the result to be
8f14e45fceea167a5a36dedd4bea2543,1679091c5a880faf6fb5e6087eb1b2dc,e4da3b7fbbce2345d7772b0674a318d5
But what I really see is
,,,8f14e45fceea167a5a36dedd4bea2543,1679091c5a880faf6fb5e6087eb1b2dc,e4da3b7fbbce2345d7772b0674a318d5
Why does iterating through the map create 6 entries instead of just 3?
https://play.golang.org/p/Ou67K1Kfvsf
With
keys := make([]string, len(supportedCards))
you create a []string with three empty elements. You can assign them using their indicies.
When you append it later, new entries are added at the end, producing your result with a length of 6, where the first three are empty.
In addition to #xarantolus's answer, instead of using indices you can keep your for-range loop unchanged by:
keys := make([]string, 0, len(supportedCards))
The third argument is capacity of the slide. Ref: https://tour.golang.org/moretypes/13
I need to construct a matrix; a number of columns and rows are also in the first row of the matrix, I'll make an example so its more clearer.
4 3
1 2 3
5 6 7
9 10 8
1 11 13
Where m=4 (number of rows) and n=3 (number of columns)
This is an example of a text file. Is something like this even possible?
Program Feb;
const
max=100;
type
Matrix=array[1..max,1..max] of integer;
var datoteka:text;
m,n:integer;
counter:integer;
begin
assign(datoteka,'datoteka.txt');
reset(datoteka);
while not eoln(datoteka) do
begin
read(datoteka, m);
read(datoteka, n);
end;
repeat
read eoln(n)
until eof(datoteka)
write (m,n);
end.
My code isn't a big help, cause I don't know how to write it.
First, have a look at the code I wrote to do the task, and then look at my explanation below.
program Matrixtest;
uses
sysutils;
var
NoOfCols,
NoOfRows : Integer;
Source : TextFile;
Matrix : array of array of integer;
FileName : String;
Row,
Col : Integer; // for-loop iterators to access a single cell of the matrix
Value : Integer;
begin
// First, construct the name of the file defining the matrix
// This assumes that the file is in the same folder as this app
FileName := ExtractFilePath(ParamStr(0)) + 'MatrixDef.Txt';
writeln(FileName); // echo it back to the screen so we can see it
// Next, open the file
Assign(Source, FileName);
Reset(Source);
read(Source, NoOfRows, NoOfCols);
writeln('Cols: ', NoOfCols, 'Rows: ', NoOfRows);
SetLength(Matrix, NoOfCols, NoOfRows);
readln(source); // move to next line in file
// Next, read the array data
for Row := 1 to NoOfRows do begin
for Col := 1 to NoOfCols do begin
read(Source, Value);
Matrix[Col - 1, Row - 1] := Value;
end;
end;
// Display the array contents
for Row := 1 to NoOfRows do begin
for Col := 1 to NoOfCols do begin
writeln('Row: ', Row, ' contents', Matrix[Col - 1, Row - 1]);
end;
end;
Close(Source); // We're done with the file, so close it to release OS resources
readln; // this waits until you press a key, so you can read what's been displayed
end.
In your program, you can use a two-dimensional array to represent your matrix. Free Pascal supports multi-dimensional arrays; see https://wiki.lazarus.freepascal.org/Multidimensional_arrays for more information.
This is a complex task, so it helps to know how to do more basic things like reading an array of a size known at compile-time from a text file.
The wrinkle in this task is that you are supposed to read the dimensions (numbers of rows and columns) of the matrix at run-time from the file which contains the matrix's contents.
One inefficient way to do this would be to declare the matrix array with huge dimensions, larger than anything you would expect in practice, using the type of array declaration in the Wiki page linked above.
A better way is to use dynamic arrays, whose dimensions you can set at run-time. To use this, you need to know:
How to declare a dynamic array in Free Pascal
How to set the dimensions of the array at run-time, once you've picked them up from your matrix-definition file (hint: SetLength is the way to do this)
The fact that a Free Pascal dynamic array is zero-based
The easiest way of managing zero-based arrays is to write your code (in terms of Row and Column variables) as if the matrix were declared as array[1..NoOfRows, 1..NoOfColumns] and subtract one from the array indexes only when you actually access the array, as in:
Row := 3;
Column := 4;
Value := Matrix[Row - 1, Column - 1];
I have a list of values that range anywhere from 500-1000. I have a second list of values that denote relevant breakpoints in the 500-1000 range (500, 520, 540, 600, etc). I need to return the highest value in the second list that is less than the value in a given number from the first list. I noticed the "N" functions let you set a conditional on them, so for example if I do:
List.Max(List.FirstN(SomeTable[Breakpoints], each _ < 530))
It correctly returns 520 to me. However if I put this inside an AddColumn function and change the 530 to a local field reference:
Table.AddColumn(MyTable, "MinValue", each List.Max(List.FirstN(SomeTable[Breakpoints], each _ < [SomeNumbers])))
Then I get a "We cannot apply field access to the type Number" error. Is what I'm trying to do possible and I'm just formatting it wrong? I always get confused with scope and references in PQ, so it may just be that.
After each, [SomeNumbers] by itself is short for _[SomeNumbers] (which is what you see when filtering a column). In the List.FirstN call, _ refers to a number in the list instead of a row in a table: the value of _ is tied to the closest each, where closeness is measured by the number of layers of nesting between _ and the appearance of each . Therefore, in your code [SomeNumbers] is trying to find the column SomeNumbers on a number, which doesn't exist.
There are a couple ways to fix this:
You can use a let...in statement to store the current value of the SomeNumbers column to use it for later, like so:
each
let
currentNumber = [SomeNumbers],
result = List.Max(List.FirstN(SomeTable[Breakpoints], each _ < currentNumber))
in
result
You can explicitly define a function with the (x) => ... syntax instead of using each twice, like so:
each List.Max(List.FirstN(SomeTable[Breakpoints], (point) => point < [SomeNumbers]))
I am trying to set the bird group as two numbers so that when I assign a variable I can use multiple "else if" statements with that one group later on
Code:
Xcode doesn't let me do this I'm in Swift
Let birdgroup: UInt32 = 2, 3
You can use Array, Set, or a tuple to store multiple values in a single variable. If order matters, go with Array or tuple, but if the order doesn't matter, you can use Set. Array and Set both allow you to vary the number of values stored in your variable, while a tuple variable must always be the same length. Also, you can loop over the items in an array or set, but not over a tuple.
Array is the most often used of the three, so if you aren't sure which to use, it's a good first choice.
In summary, this table shows the possibilities and their properties:
Loopable Unloopable
Ordered Array Tuple
Unordered Set (none)
Finally, all the items in an array or set must be of the same type (or derived from the same type, if the array or set is defined with the base class). This is called homogeneous. A tuple can contain different types, also known as heterogeneous.
Homogeneous Heterogeneous
Ordered Array Tuple
Unordered Set (none)
Collection Types in the Swift documentation describes how to use Array and Set.
Array
Create an array with
var birdgroup: [UInt32] = [2, 3]
birdgroup[0] is equal to 2, and birdgroup[1] is equal to 3. You can also access the items by looping:
for bird in birdgroup {
println("\(bird)")
}
Set
You can declare a set with
var birdgroup: Set<UInt32> = [2, 3]
Because sets have no order (imagine every item is tossed together in a bag), you can't request the "first" or "second" item. Instead, loop over each item of the set:
for bird in birdgroup {
println("\(bird)")
}
Tuple
let birdgroup: (UInt32, UInt32) = (2, 3)
Tuples also retain the order of their items. birdgroup.0 is equal to 2, and birdgroup.1 to 3. You can also give each item of the tuple a name if you prefer that to a number:
let birdgroup: (UInt32, UInt32) = (foo: 2, bar: 3)
birdgroup.foo is 2, and birdgroup.bar is 3.
Additionally, the values in a tuple do not all need to be the same type. You can combine different types, such as
let heterogeneousTuple: (UInt32, String) = (2, "three")