Overpass-api comparison operators - comparison-operators

In the post "Date ranges with Overpass API" Roland Olbricht announced public beta for the next Overpass API release. I try to use the comparison operators "==", "<", "<=", ">", and ">=" to find nodes with tag population which is greater then or smaller then any number
node[population]
(if:"population">5834)({{bbox}});
(._;>;);
out;
unfortunately comparison operators seems not to work at all. I try function number()
node[population]
(if:number("population")>5834)({{bbox}});
(._;>;);
out;
One thing that works is code like this
node[population]
(if:!is_number("population"))({{bbox}});
(._;>;);
out;
therefore I have a question whether anyone had contact with the beta and these operators?

The updated documentation has been published on the OSM Wiki in the meantime: http://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL
For your use case, you need to use the following syntax to:
Find all nodes with population tag in the current bbox
That have a population numeric tag
Where the actual value of the population tag is larger than 5834:
Query:
node[population]
(if: is_number(t[population]) && number(t[population])>5834 )
({{bbox}});
out;
Due to automatic type conversions you should also be able to use the following shorter variant:
node[population] (if: t[population] > 5834)({{bbox}});
out;

Related

Not able to use for loop in ternary operator in arangodb

How do we write conditions in arango, that includes for loops. I can elaborate the requirement below.
My requirement is if a particular attribute(array type) exists in the arango collection, i would read data from the collection(that requires a loop) or else, might do the following :
return null
return empty string ""
do nothing.
Is this possible to achieve in arango?
The helping methods could be -->
-- has(collectionname, attributename)
-- The ternary operator ?:
let attribute1 = has(doc,"attribute1") ?(
for name in doc.attribute1.names
filter name.language == "xyz"
return name.name
) : ""
But this dosent work. Seems like arango compiler first attempts to compile the for loop, finds nulls and reports error as below. Instead, it should have compiled "has" function first for the ternary operator being used.
collection or array expected as operand to FOR loop; you provided a value of type 'null' (while executing)
If there is a better way of doing it, would appreciate the advice!!
Thanks in advance!
Nilotpal
Fakhrany here from ArangoDB.
Regarding your question, this is a known limitation.
From https://www.arangodb.com/docs/3.8/aql/fundamentals-limitations.html:
The following other limitations are known for AQL queries:
Subqueries that are used inside expressions are pulled out of these
expressions and executed beforehand. That means that subqueries do not
participate in lazy evaluation of operands, for example in the ternary
operator. Also see evaluation of subqueries.
Also noted here for the ternary operator:
https://www.arangodb.com/docs/3.8/aql/operators.html#ternary-operator.
An answer to the question what to do may be to use a FILTER before enumerating over the attributes:
FOR doc IN collection
/* the following filter will only let those documents passed in which "attribute1.names" is an array */
FILTER IS_ARRAY(doc.attribute1.names)
FOR name IN doc.attribute1.names
FILTER name.language == "xyz"
RETURN name.name
Other solutions are also possible. Depends a bit on the use case.

Nested IF statement returning false

I have a nested if statement is returning "False" rather than the expected outcome.
Scenario
Table "High VoltageCables" has data in it that default to numeric but may contain characters: kVa
Table "Master" checks "High VoltageCables" data as blank or not blank, and returns "Failed Check 1","Passed Check 1". This works fine.
Table "Meta" then checks the results of "Master" and then tests "High VoltageCables" data for length between 1 and 6, regardless of whether record is numeric or string.
Formula
=IF(MASTER!H2="Passed Check 1",IF(LEN('High VoltageCables'!O2)>=1,IF(LEN('High VoltageCables'!O2<6),"Passed Check 2","Failed Check 2")))
This is partially succesful, as it returns "Passed Check 2" for the following sample data in the source table "High VoltageCables".
1 numeric, or
1kVa str, or
50000 numeric
However if a field in "High VoltageCables"is blank, the formula returns "FALSE" rather than "Failed Check 1"
I inherited this task, (and would have preferred to do the whole thing in Access using relatively simple queries) - and unfortunately I am new to nested If statements, so I am probably missing something basic...
NB the data in High VoltageCables must default to numeric for a further check to work.
The first and second IF's seem to be missing the else part. They should be added at the end between the ))) like ), else ), else )
Every IF statement consists of IF( condition, truepart, falsepart) if you have two nested ifs it will be something like IF( condition, IF( condition2, truepart2, falsepart2), falsepart)
Hope that makes it a little clearer
You do have an unaccounted for FALSE in the middle IF. Try bring the latter two conditions together.
=IF(Master!H2="Passed Check 1",IF(OR(LEN('High VoltageCables'!O2)={1,2,3,4,5}),"Passed Check 2","Failed Check 2"))
It's still a bit unclear on what to show or not show if Master!H2 does not equal "Passed Check 1".
I failed to construct the formula with a concluding "else" - "Failed Check 1"
Using jeeped's and Tom's suggestion and adding the final "else" part I have solved the problem:
=IF(MASTER!H2="Passed Check 1",IF(OR(LEN('High VoltageCables'!O2)={1,2,3,4,5}),"Passed Check 2","Failed Check 2"),"Failed Check 1")

Cognos query calculation - how to obtain a null/blank value?

I have a query calculation that should throw me either a value (if conditions are met) or a blank/null value.
The code is in the following form:
if([attribute] > 3)
then ('value')
else ('')
At the moment the only way I could find to obtain the result is the use of '' (i.e. an empty character string), but this a value as well, so when I subsequently count the number of distinct values in another query I struggle to get the correct number (the empty string should be removed from the count, if found).
I can get the result with the following code:
if (attribute='') in ([first_query].[attribute]))
then (count(distinct(attribute)-1)
else (count(distinct(attribute))
How to avoid the double calculation in all later queries involving the count of attribute?
I use this Cognos function:
nullif(1, 1)
I found out that this can be managed using the case when function:
case
when ([attribute] > 3)
then ('value')
end
The difference is that case when doesn't need to have all the possible options for Handling data, and if it founds a case that is not in the list it just returns a blank cell.
Perfect for what I needed (and not as well documented on the web as the opposite case, i.e. dealing with null cases that should be zero).

How to remove percent character from a string in Cognos?

I have a string field with mostly numeric values like 13.4, but some have 13.4%. I am trying to use the following expression to remove the % symbols and retain just the numeric values to convert the field to integer.
Here is what I have so far in the expression definition of Cognos 8 Report Studio:
IF(POSITION('%' IN [FIELD1]) = NULL) THEN
/*** this captures rows with valid data **/
([FIELD1])
ELSE
/** trying to remove the % sign from rows with data like this 13.4% **/
(SUBSTRING([FIELD1]), 1, POSITION('%' IN [FIELD1])))
Any hints/help is much appreciated.
An easy way to do this is to use the trim() function. The following will remove any trailing % characters:
TRIM(trailing '%',[FIELD1])
The approach you are using is feasable. However, the syntax you are using is not compatible with the version of the ReportStudio that I'm familiar with. Below you will find an updated expression which works for me.
IF ( POSITION( '%'; [FIELD1]) = 0) THEN
( [FIELD1] )
ELSE
( SUBSTRING( [FIELD1]; 1; POSITION( '%'; [FIELD1]) - 1 ) )
Since character positions in strings are 1-based in Cognos it's important to substract 1 from the position returned by POSITION(). Otherwise you would only cut off characters after the percent sign.
Another note: what you are doing here is data cleansing. It's usually more advantageous to push these chores down to a lower level of the data retrieval chain, e.g. the Data Warehouse or at least the Framework Manager model, so that at the reporting level you can use this field as numeric field directly.

C# 4.0 function to check for first four characters in the string

I need to validate for valid code name.
So, my string can have values like below:
String test = "C000. ", "C010. ", "C020. ", "C030. ", "CA00. ","C0B0. ","C00C. "
So my function needs to validate below conditions:
It should start with C
After that next 3 characters should be numeric before .
Rest it can be anything.
So in above string values, only ["C000.", "C010.", "C020.", "C030."] are valid ones.
EDIT:
Below is the code I tried:
if (nameObject.Title.StartsWith(String.Format("^[C][0-9]{3}$",nameObject.Title)))
I'd suggest a regex, for example (written off the top of my head, may need work):
string s = "C030.";
Regex reg = new Regex("C[0-9]{3,3}\\.");
bool isMatch = reg.IsMatch(s);
This regex should do the trick:
Regex.IsMatch(input, #"C[0-9]{3}\..*")
Check out http://www.techotopia.com/index.php/Working_with_Strings_in_C_Sharp
for a quick tutorial on (among other things) individual access of string elements, so you can test each element for your criteria.
If you think your criteria may change, using regular expressions gives you maximum flexibility (but is more runtime intensive than regular string-element evaluation). In your case, it may be overkill, IMHO.

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