I'm looking for an algorithm to take a string displaying a sum and add the relevant parentheses where required. For example:
Given: 1+2*3=7 it would return 1+(2*3)=7
Given: 5*2+10/5-4=8 it would return (5*2)+(10/5)-4=8
Related
Write a recursive method that computes the sum of the sum of the digits in an integer. use the following method header:
public static int sumDigits(long n)
For example, sumDigits(234) returns 2 + 3 + 4 = 9. Write a real program that prompts the user to enter an integer and displays its sum.
Receive an integer as a parameter
Convert to string
Parse the string's individual characters
Remove a character (first or last doesn't matter)
Put the remaining characters back into a single string
Cast that string back to integer
Call "result = removedChar As Integer + function(remainingChars as Integer)" <--- this is the recursion
In the future you should at least make one attempt for others to help you edit when you post an obvious homework question ;)
Starting with complex reduce sample
I have trimmed it down to a single chart and I am trying to understand how the reduce works
I have made comments in the code that were not in the example denoting what I think is happening based on how I read the docs.
function groupArrayAdd(keyfn) {
var bisect = d3.bisector(keyfn); //set the bisector value function
//elements is the group that we are reducing,item is the current item
//this is a the reduce function being supplied to the reduce call on the group runAvgGroup for add below
return function(elements, item) {
//get the position of the key value for this element in the sorted array and put it there
var pos = bisect.right(elements, keyfn(item));
elements.splice(pos, 0, item);
return elements;
};
}
function groupArrayRemove(keyfn) {
var bisect = d3.bisector(keyfn);//set the bisector value function
//elements is the group that we are reducing,item is the current item
//this is a the reduce function being supplied to the reduce call on the group runAvgGroup for remove below
return function(elements, item) {
//get the position of the key value for this element in the sorted array and splice it out
var pos = bisect.left(elements, keyfn(item));
if(keyfn(elements[pos])===keyfn(item))
elements.splice(pos, 1);
return elements;
};
}
function groupArrayInit() {
//for each key found by the key function return this array?
return []; //the result array for where the data is being inserted in sorted order?
}
I am not quite sure my perception of how this is working is quite right. Some of the magic isn't showing itself. Am I correct that elements is the group the reduce function is being called on ? also the array in groupArrayInit() how is it being indirectly populated?
Part of me feels that the functions supplied to the reduce call are really array.map functions not array.reduce functions but I just can't quite put my finger on why. having read the docs I am just not making a connection here.
Any help would be appreciated.
Also have I missed Pens/Fiddles that are created for all these examples? like this one
http://dc-js.github.io/dc.js/examples/complex-reduce.html which is where I started with this but had to download the csv and manually convert to Json.
--------------Update
I added some print statements to try to clarify how the add function is working
function groupArrayAdd(keyfn) {
var bisect = d3.bisector(keyfn); //set the bisector value function
//elements is the group that we are reducing,item is the current item
//this is a the reduce function being supplied to the reduce call on the group runAvgGroup for add below
return function(elements, item) {
console.log("---Start Elements and Item and keyfn(item)----")
console.log(elements) //elements grouped by run?
console.log(item) //not seeing the pattern on what this is on each run
console.log(keyfn(item))
console.log("---End----")
//get the position of the key value for this element in the sorted array and put it there
var pos = bisect.right(elements, keyfn(item));
elements.splice(pos, 0, item);
return elements;
};
}
and to print out the group's contents
console.log("RunAvgGroup")
console.log(runAvgGroup.top(Infinity))
which results in
Which appears to be incorrect b/c the values are not sorted by key (the run number)?
And looking at the results of the print statements doesn't seem to help either.
This looks basically right to me. The issues are just conceptual.
Crossfilter’s group.reduce is not exactly like either Array.reduce or Array.map. Group.reduce defines methods for handling adding new records to a group or removing records from a group. So it is conceptually similar to an incremental Array.reduce that supports an reversal operation. This allows filters to be applied and removed.
Group.top returns your list of groups. The value property of these groups should be the elements value that your reduce functions return. The key of the group is the value returned by your group accessor (defined in the dimension.group call that creates your group) or your dimension accessor if you didn’t define a group accessor. Reduce functions work only on the group values and do not have direct access to the group key.
So check those values in the group.top output and hopefully you’ll see the lists of elements you expect.
Like many, I'm tackling the Mondial database on XML. It would be a piece of cake, if XQuery syntax wasn't doing its best to sabotage.
let $inland := //province/#id
where every $sea in //sea satisfies
$sea/located/#province != $inland
return $inland
What I am trying to do in the above is find all "inland" provinces, the provinces that don't have a sea next to it. This, however, doesn't work, because the $sea/located/province is a big string, with every single province that it borders in it.
So I tried to modify into.
let $inland := //province/#id
where every $sea in //sea satisfies
not(contains($sea/located/#province, $inland))
return $inland
Where I would like it to only find the provinces that are a part of the sea's bordering provinces. Simple and straightforward.
Error message:
Stopped at C:/Users/saffekaffe/Desktop/mondial/xml/country_without_island.xml, 2/1:
[XPTY0004] Item expected, sequence found: (attribute id {"prov-Greece-2"},....
How do I get around this?
Example of //sea/located/province#
province="prov-France-5 prov-France-20 prov-France-89 prov-France-99"
Example of //province/#id
id="prov-Greece-2"
There are multiple ways in which XQuery works in a different way than you seem to expect.
The comparison operators = and != have existential semantics if at least one of their arguments is a sequence instead of a single item. This means that $seq1 = $seq2 is equivalent to some $x in $seq1, $y in $seq2 satisfies $x = $y. The query ('foo', 'bar') = ('bar', 'baz', 'quuz') returns true because there is at least one common item.
An XQuery exception like //province/#id evaluates to a sequence of all matching nodes. In your case that would be a sequence of over 1000 province IDs: (id="prov-cid-cia-Greece-2", id="prov-cid-cia-Greece-3", id="prov-cid-cia-Greece-4", [...]). This sequence is then bound to the variable $inland in your let clause. Since you don't iterate over individual items in $inland (for example using a for clause), the where condition then works on the whole sequence of all provinces worldwide at once. So your condition every $sea in //sea satisfies
$sea/located/#province != $inland now means:
"For every sea there is a province located next to it that has an #id that is not equal to at least one of all existing province IDs."
Th is returns false because there are seas with no located children, e.g.the Gulf of Aden.
contains($str, $sub) is not a good fit for checking if a substring is contained in a space-delimited string, because it also matches parts of entries: contains("foobar baz quux", "oob") returns true.
Instead you should either split the string into its parts using tokenize($str) and look through its parts, or use contains-token($str, $token).
Putting it all together, a correct query very similar to your original one is:
for $inland in //province/#id
where
every $sea in //sea
satisfies not(contains-token($sea/located/#province, $inland))
return $inland
Another approach would be to first gather all (unique) provinces that are next to seas and then return all provinces not in that sequence:
let $next-to-sea := distinct-values(//sea/located/#province/tokenize(.))
return //province/#id[not(. = $next-to-sea)]
Even more compact (but potentially less efficient):
//province/#id[not(. = //sea/located/#province/tokenize(.))]
On the other end of the spectrum you can use XQuery 3.0 maps to replace the potentially linear search through all seaside provinces by a single lookup:
let $seaside :=
map:merge(
for $id in //sea/located/#province/tokenize(.)
return map{ $id: () }
)
return //province/#id[not(map:contains($seaside, .))]
I want to create a model where I can add numbers to that specific column and it will return a string concatenating a string and the value put in the cell.
Example:
When writing a value 123 to the cell, it will return a string say "http:// www.link.com/" concatenated with the value of the value 123 (as string).
Resulting -> http:// www.link.com/123
Use the operand &
For example, use this formula the result cell:
="http:// ww.link.com/"&A1
It will use A1 cell value to concatenate to your string
Following should return Y
CASISA#Y
INVOPT#LUMREG#LUMSUM#2000#REGSUM#8000
LUMSUM#2000#REGSUM#8000
i.e Hash separates Code and Value and it also separates Code, Value pairs (earlier semicolon used to separate Code, Value pairs)
Following should return N (as these are incorrect input string formats)
CASISA#
INVOPT#LUMREG#LUMSUM
LUMSUM#2000#REGSUM#8000#
case when regexp_like(your_string||'#', '^(\w+#\w+#)+$') then 'Y' else 'N' end
SQL Fiddle