scala increment nested for comprehension - scala

I am working on detecting PI/SI information within given dataset(spark). I have set of rules (in csv format) as below
Rule_No,Target,Pattern,Fuzzy_Match,EPDR,Category,Active
1,Name,name,true,PI - Name,General/ID,true
1,Name,identity,true,PI - Name,General/ID,true
1,Content,Smith,true,PI - Name,General/ID,true
1,Content,Jones,true,PI - Name,General/ID,true
1,Content,Williams,true,PI - Name,General/ID,true
5,Name,Gender,true,PI - Gender,General/ID,true
5,Content,M,false,PI - Gender,General/ID,true
5,Content,F,false,PI - Gender,General/ID,true
5,Content,Male,false,PI - Gender,General/ID,true
5,Content,Female,false,PI - Gender,General/ID,true
What I am trying to do is iterate over dataset columns and apply each of these rules to check whether particular column has PII or not.
So say if I have column called name and given rule says scan the content of this column with pattern say Smith. If I found the match I will know this column is PI column and then move to next column and apply each and every rule until I find a match.
I am using nested for comprehension to iterate over list of columns and list of rules. What I want is when I find a match I want to move to the next column instead of applying remaining rules.
I have written code like this
for {
c <- ds.columns.toList
rule <- rules if rule.active && checkPII(ds, c, rule.target, rule.pattern, rule.fuzzyMatch)
} yield {
<return PII information>
}
but this will apply every rule to same column even if it gets match. How can I move to next column instead of keep applying remaining rules?

for turns into a map call which always checks every elements. You need to use collectFirst, which stops at the first match.
ds.columns.toList.flatMap { c =>
rules.collectFirst {
case rule if rule.active && checkPII(ds, c, rule.target, rule.pattern, rule.fuzzyMatch) =>
<return PII information>
}
}
Using flatMap means that it will discard failed matches and just return a list of matching values.

Related

Transforming `PCollection` with many elements into a single element

I am trying to convert a PCollection, that has many elements, into a PCollection that has one element. Basically, I want to go from:
[1,2,3,4,5,6]
to:
[[1,2,3,4,5,6]]
so that I can work with the entire PCollection in a DoFn.
I've tried CombineGlobally(lamdba x: x), but only a portion of elements get combined into an array at a time, giving me the following result:
[1,2,3,4,5,6] -> [[1,2],[3,4],[5,6]]
Or something to that effect.
This is my relevant portion of my script that I'm trying to run:
import apache_beam as beam
raw_input = range(1024)
def run_test():
with TestPipeline() as test_pl:
input = test_pl | "Create" >> beam.Create(raw_input)
def combine(x):
print(x)
return x
(
input
| "Global aggregation" >> beam.CombineGlobally(combine)
)
pl.run()
run_test()
I figured out a pretty painless way to do this, which I missed in the docs:
The more general way to combine elements, and the most flexible, is
with a class that inherits from CombineFn.
CombineFn.create_accumulator(): This creates an empty accumulator. For
example, an empty accumulator for a sum would be 0, while an empty
accumulator for a product (multiplication) would be 1.
CombineFn.add_input(): Called once per element. Takes an accumulator
and an input element, combines them and returns the updated
accumulator.
CombineFn.merge_accumulators(): Multiple accumulators could be
processed in parallel, so this function helps merging them into a
single accumulator.
CombineFn.extract_output(): It allows to do additional calculations
before extracting a result.
I suppose supplying a lambda function that simply passes its argument to the "vanilla" CombineGlobally wouldn't do what I expected initially. That functionality has to be specified by me (although I still think it's weird this isn't built into the API).
You can find more about subclassing CombineFn here, which I found very helpful:
A CombineFn specifies how multiple values in all or part of a
PCollection can be merged into a single value—essentially providing
the same kind of information as the arguments to the Python “reduce”
builtin (except for the input argument, which is an instance of
CombineFnProcessContext). The combining process proceeds as follows:
Input values are partitioned into one or more batches.
For each batch, the create_accumulator method is invoked to create a fresh initial “accumulator” value representing the combination of
zero values.
For each input value in the batch, the add_input method is invoked to combine more values with the accumulator for that batch.
The merge_accumulators method is invoked to combine accumulators from separate batches into a single combined output accumulator value,
once all of the accumulators have had all the input value in their
batches added to them. This operation is invoked repeatedly, until
there is only one accumulator value left.
The extract_output operation is invoked on the final accumulator to get the output value. Note: If this CombineFn is used with a transform
that has defaults, apply will be called with an empty list at
expansion time to get the default value.
So, by subclassing CombineFn, I wrote this simple implementation, Aggregated, that does exactly what I want:
import apache_beam as beam
raw_input = range(1024)
class Aggregated(beam.CombineFn):
def create_accumulator(self):
return []
def add_input(self, accumulator, element):
accumulator.append(element)
return accumulator
def merge_accumulators(self, accumulators):
merged = []
for a in accumulators:
for item in a:
merged.append(item)
return merged
def extract_output(self, accumulator):
return accumulator
def run_test():
with TestPipeline() as test_pl:
input = test_pl | "Create" >> beam.Create(raw_input)
(
input
| "Global aggregation" >> beam.CombineGlobally(Aggregated())
| "print" >> beam.Map(print)
)
pl.run()
run_test()
You can also accomplish what you want with side inputs, e.g.
with beam.Pipeline() as p:
pcoll = ...
(p
# Create a PCollection with a single element.
| beam.Create([None])
# This will process the singleton exactly once,
# with the entirity of pcoll passed in as a second argument as a list.
| beam.Map(
lambda _, pcoll_as_side: ...consume pcoll_as_side here...,
pcoll_as_side=beam.pvalue.AsList(pcoll))

How can I convert this select statement to functional form?

I am having a couple of issues to put this in a functional format.
select from tableName where i=fby[(last;i);([]column_one;column_two)]
This is what I got:
?[tableName;fby;enlist(=;`i;(enlist;last;`i);(+:;(!;enlist`column_one`column_two;(enlist;`column_one;`column_two))));0b;()]
but I get a type error.
Any suggestions?
Consider using the following function, adjust from the buildQuery function given in the whitepaper on Parse Trees. This is a pretty useful tool for quickly developing in q, this version is an improvement on that given in the linked whitepaper, having been extended to handle updates by reference (i.e., update x:3 from `tab)
\c 30 200
tidy:{ssr/[;("\"~~";"~~\"");("";"")] $[","=first x;1_x;x]};
strBrk:{y,(";" sv x),z};
//replace k representation with equivalent q keyword
kreplace:{[x] $[`=qval:.q?x;x;"~~",string[qval],"~~"]};
funcK:{$[0=t:type x;.z.s each x;t<100h;x;kreplace x]};
//replace eg ,`FD`ABC`DEF with "enlist`FD`ABC`DEF"
ereplace:{"~~enlist",(.Q.s1 first x),"~~"};
ereptest:{((0=type x) & (1=count x) & (11=type first x)) | ((11=type x)&(1=count x))};
funcEn:{$[ereptest x;ereplace x;0=type x;.z.s each x;x]};
basic:{tidy .Q.s1 funcK funcEn x};
addbraks:{"(",x,")"};
//where clause needs to be a list of where clauses, so if only one whereclause need to enlist.
stringify:{$[(0=type x) & 1=count x;"enlist ";""],basic x};
//if a dictionary apply to both, keys and values
ab:{$[(0=count x) | -1=type x;.Q.s1 x;99=type x;(addbraks stringify key x),"!",stringify value x;stringify x]};
inner:{[x]
idxs:2 3 4 5 6 inter ainds:til count x;
x:#[x;idxs;'[ab;eval]];
if[6 in idxs;x[6]:ssr/[;("hopen";"hclose");("iasc";"idesc")] x[6]];
//for select statements within select statements
//This line has been adjusted
x[1]:$[-11=type x 1;x 1;$[11h=type x 1;[idxs,:1;"`",string first x 1];[idxs,:1;.z.s x 1]]];
x:#[x;ainds except idxs;string];
x[0],strBrk[1_x;"[";"]"]
};
buildSelect:{[x]
inner parse x
};
We can use this to create the functional query that will work
q)n:1000
q)tab:([]sym:n?`3;col1:n?100.0;col2:n?10.0)
q)buildSelect "select from tab where i=fby[(last;i);([]col1;col2)]"
"?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]"
So we have the following as the functional form
?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]
// Applying this
q)?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]
sym col1 col2
----------------------
bah 18.70281 3.927524
jjb 35.95293 5.170911
ihm 48.09078 5.159796
...
Glad you were able to fix your problem with converting your query to functional form.
Generally it is the case that when you use parse with a fby in your statement, q will convert this function into its k definition. Usually you should just be able to replace this k code with the q function itself (i.e. change (k){stuff} to fby) and this should run properly when turning the query into functional form.
Additionally, if you check out https://code.kx.com/v2/wp/parse-trees/ it goes into more detail about parse trees and functional form. Additionally, it contains a script called buildQuery which will return the functional form of the query of interest as a string which can be quite handy and save time when a functional form is complex.
I actually got it myself ->
?[tableName;((=;`i;(fby;(enlist;last;`i);(+:;(!;enlist`column_one`column_two;(enlist;`column_one;`column_two)))));(in;`venue;enlist`venueone`venuetwo));0b;()]
The issues was a () missing from the statement. Works fine now.
**if someone wants to add a more detailed explanation on how manual parse trees are built and how the generic (k){} function can be replaced with the actual function in q feel free to add your answer and I'll accept and upvote it

Drools compare two objects in decision table

I have the following code in DRL file
rule "MyExample"
when
$eentity : ExampleEntity()
$sentity : SecondEntity( secondField == $eentity.getMainField())
then
System.out.println(true);
end
This is works but I need to convert it to spreadsheet table. I tried so much variants but no one works. How can I write this rule in decision table?
Use a single condition column:
CONDITION
ExampleEntity($mf: mainField) SecondEntity
secondField == $mf /*param*/
Combine Ex with Sec on equal field values
x
The /*param*/ and the x is a hack to get the condition being generated for the row.

Matching a list (of tags) with another and detecting presence of common elements

My requirement is to match tags. In the example, this particular HourConstraint checks the TeacherHour assigned to Hour(23).
Specifically, it checks TeacherHour.attributes["tags"] for the values ["asst_ct","teacher_john_smith"] and detects atleast one match, two in this case (both "asst_ct" and "teacher_john_smith") .
TeacherHour:
id: 47
assigned_hour: Null
attributes:Map<List<String>>
"tags":["asst_ct","no_strenuous_duties","kinda_boring","teacher_john_smith"]
"another_attribute":[...]
HourConstraint:
hour: Hour(23)
attribute: "tags"
values_list: ["asst_ct","teacher_john_smith"]
Question: How do I detect the presence (true or false) of common elements between two lists?
Drools Expert has memberOf and contains, but they check a scalar vs a collection, never a collection vs a collection.
I see two potential ways:
introduce a function boolean isIntersecting(list,list) and tell Drools to use that for truth checking
Implement TeacherHour.attributes[] as a string instead of a list and HourConstraint.valueslist as a regular expression that can match that list
There are a few options. Most straight forward is to use the Collections class to do that for you:
rule X
when
$t: TeacherHour( )
HourConstraint( Collections.disjoint( $t.attributes["tags"], values_list ) == false )
...
If this is something you would use often in your rules, then I recommend wrapping that function in a pluggable operator, supported by Drools. Lets say you name the operator "intersect", you can then write your rules like this:
rule X
when
$t: TeacherHour( )
HourConstraint( values_list intersect $t.attributes["tags"] )
...
A third option, is to use "from", but that is less efficient in runtime as it causes iterations on the first list:
rule X
when
$t: TeacherHour( )
$tag : String() from $t.attributes["tags"]
exists( HourConstraint( values_list contains $tag ) )
...

Best way to create generic/method consistency for sort.data.frame?

I've finally decided to put the sort.data.frame method that's floating around the internet into an R package. It just gets requested too much to be left to an ad hoc method of distribution.
However, it's written with arguments that make it incompatible with the generic sort function:
sort(x,decreasing,...)
sort.data.frame(form,dat)
If I change sort.data.frame to take decreasing as an argument as in sort.data.frame(form,decreasing,dat) and discard decreasing, then it loses its simplicity because you'll always have to specify dat= and can't really use positional arguments. If I add it to the end as in sort.data.frame(form,dat,decreasing), then the order doesn't match with the generic function. If I hope that decreasing gets caught up in the dots `sort.data.frame(form,dat,...), then when using position-based matching I believe the generic function will assign the second position to decreasing and it will get discarded. What's the best way to harmonize these two functions?
The full function is:
# Sort a data frame
sort.data.frame <- function(form,dat){
# Author: Kevin Wright
# http://tolstoy.newcastle.edu.au/R/help/04/09/4300.html
# Some ideas from Andy Liaw
# http://tolstoy.newcastle.edu.au/R/help/04/07/1076.html
# Use + for ascending, - for decending.
# Sorting is left to right in the formula
# Useage is either of the following:
# sort.data.frame(~Block-Variety,Oats)
# sort.data.frame(Oats,~-Variety+Block)
# If dat is the formula, then switch form and dat
if(inherits(dat,"formula")){
f=dat
dat=form
form=f
}
if(form[[1]] != "~") {
stop("Formula must be one-sided.")
}
# Make the formula into character and remove spaces
formc <- as.character(form[2])
formc <- gsub(" ","",formc)
# If the first character is not + or -, add +
if(!is.element(substring(formc,1,1),c("+","-"))) {
formc <- paste("+",formc,sep="")
}
# Extract the variables from the formula
vars <- unlist(strsplit(formc, "[\\+\\-]"))
vars <- vars[vars!=""] # Remove spurious "" terms
# Build a list of arguments to pass to "order" function
calllist <- list()
pos=1 # Position of + or -
for(i in 1:length(vars)){
varsign <- substring(formc,pos,pos)
pos <- pos+1+nchar(vars[i])
if(is.factor(dat[,vars[i]])){
if(varsign=="-")
calllist[[i]] <- -rank(dat[,vars[i]])
else
calllist[[i]] <- rank(dat[,vars[i]])
}
else {
if(varsign=="-")
calllist[[i]] <- -dat[,vars[i]]
else
calllist[[i]] <- dat[,vars[i]]
}
}
dat[do.call("order",calllist),]
}
Example:
library(datasets)
sort.data.frame(~len+dose,ToothGrowth)
Use the arrange function in plyr. It allows you to individually pick which variables should be in ascending and descending order:
arrange(ToothGrowth, len, dose)
arrange(ToothGrowth, desc(len), dose)
arrange(ToothGrowth, len, desc(dose))
arrange(ToothGrowth, desc(len), desc(dose))
It also has an elegant implementation:
arrange <- function (df, ...) {
ord <- eval(substitute(order(...)), df, parent.frame())
unrowname(df[ord, ])
}
And desc is just an ordinary function:
desc <- function (x) -xtfrm(x)
Reading the help for xtfrm is highly recommended if you're writing this sort of function.
There are a few problems there. sort.data.frame needs to have the same arguments as the generic, so at a minimum it needs to be
sort.data.frame(x, decreasing = FALSE, ...) {
....
}
To have dispatch work, the first argument needs to be the object dispatched on. So I would start with:
sort.data.frame(x, decreasing = FALSE, formula = ~ ., ...) {
....
}
where x is your dat, formula is your form, and we provide a default for formula to include everything. (I haven't studied your code in detail to see exactly what form represents.)
Of course, you don't need to specify decreasing in the call, so:
sort(ToothGrowth, formula = ~ len + dose)
would be how to call the function using the above specifications.
Otherwise, if you don't want sort.data.frame to be an S3 generic, call it something else and then you are free to have whatever arguments you want.
I agree with #Gavin that x must come first. I'd put the decreasing parameter after the formula though - since it probably isn't used that much, and hardly ever as a positional argument.
The formula argument would be used much more and therefore should be the second argument. I also strongly agree with #Gavin that it should be called formula, and not form.
sort.data.frame(x, formula = ~ ., decreasing = FALSE, ...) {
...
}
You might want to extend the decreasing argument to allow a logical vector where each TRUE/FALSE value corresponds to one column in the formula:
d <- data.frame(A=1:10, B=10:1)
sort(d, ~ A+B, decreasing=c(A=TRUE, B=FALSE)) # sort by decreasing A, increasing B