I have data schema like {col1:chararray,col2:int,col3:bag{}}
e.g.
{a,1,{d,e}}
{b,2,{c}}
I want to have an output like
{a,1,d}
{a,1,e}
{b,2,c}
I think it is kind of like having a cross over some columns, but I don't know how to achieve the same ? Maybe there are some other methods to get the output.
You will have to use to ToBag function and Flatten
A = LOAD 'data.txt' USING PigStorage('\t') as (col1:chararray,col2:int,col3:bag{});
B = FOREACH A GENERATE col1,col2, FLATTEN(TOBAG(col3));
Related
I am very new to Pig , so facing some issues while trying to perform very basic processing in Pig.
1- Load that file using Pig
2- Write a processing logic to filter records based on Date , for example the lines have 2 columns col_1 and col_2 ( assume the columns are chararray ) and I need to get only the records which are having 1 day difference between col_1 and col_2.
3- Finally store that filtered record in Hive table .
Input file ( tab separated ) :-
2016-01-01T16:31:40.000+01:00 2016-01-02T16:31:40.000+01:00
2017-01-01T16:31:40.000+01:00 2017-01-02T16:31:40.000+01:00
When I try
A = LOAD '/user/inp.txt' USING PigStorage('\t') as (col_1:chararray,col_2:chararray);
The result I am getting like below :-
DUMP A;
(,2016-01-03T19:28:58.000+01:00,2016-01-02T16:31:40.000+01:00)
(,2017-01-03T19:28:58.000+01:00,2017-01-02T16:31:40.000+01:00)
Not sure Why ?
Please can some one help me in this how to parse tab separated file and how to covert that chararray to Date and filter based on Day difference ?
Thanks
Convert the columns to datetime object using ToDate and use DaysBetween.This should give the difference and if the difference == 1 then filter.Finally load it hive.
A = LOAD '/user/inp.txt' USING PigStorage('\t') as (col_1:chararray,col_2:chararray);
B = FOREACH A GENERATE DaysBetween(ToDate(col_1,'yyyy-MM-dd HH:mm:ss'),ToDate(col_2,'yyyy-MM-dd HH:mm:ss')) as day_diff;
C = FILTER B BY (day_diff == 1);
STORE C INTO 'your_hive_partition' USING org.apache.hive.hcatalog.pig.HCatStorer();
I need to convert the value of a column to uppercase in pig.
Was able to do using UPPER but this creates a new column.
For example:
A = Load 'MyFile.txt' using PigStorage(',') as (column1:chararray, column2:chararray, column3:chararray);
Dump A;
Returns
a,b,c
d,e,f
Now I need to convert second column to upper case.
B = Foreach A generate *,UPPER(column2);
Dump B;
returns
a,b,c,B
e,f,g,F
But I need
a,B,c
e,F,g
Please let me know if there is a way to so.
I didn't tried from my side but you can try like this
B = Foreach A generate column1,UPPER(column2),column3;
Using the "*" in the below line is the reason for the extra column:
B = FOREACH A generate *, UPPER(column2);
Instead use the below:
B = Foreach A generate column1, UPPER(column2), column3;
You can do it with user define function that default provided by Apache pig
find PiggyBank Jar
command
find / -name "piggybank*.jar*"
now goto pig grunt shell
code
grunt> register /usr/local/pig-0.16.0/contrib/piggybank/java/piggybank.jar;
grunt> A = Load 'data/MyFile.txt' using PigStorage(',') as (column1:chararray, column2:chararray, column3:chararray);
grunt> dump A;
result
(a,b,c)
(d,e,f)
Now convert second column to upper case.
grunt> B = foreach A generate column1,org.apache.pig.piggybank.evaluation.string.UPPER(column2),column3;
grunt> dump B;
result
(a,B,c)
(d,E,f)
I want to define an array of user Ids in Pig and then filter data if the userId from the input is NOT in that array,
How do I do this in pig latin? Below is the example of what I intend to do
Thanks
inputData = load '$INPUT' USING PigStorage('|') AS (useriD:chararray,controllerAction:chararray,url:chararray,browserName:chararray,IsMobile:chararray,exceptionDetails:chararray,renderTime:int,serviceHostId:int,auditEventTime:chararray);
filteredInput = filter inputData by controllerAction is not null and auditEventTime is not null and serviceHostId is not null and renderTime is not null and useriD in ('2be2df06-f4ba-4d87-8938-09d867d3f2fe','ac1ac6bf-d151-49fc-8c7c-2b52d2efbb58','f00aec16-36e5-46ae-b7cb-a0f1eeefe609','258890f9-102a-4f8e-a001-ae24d2e25269','cf221779-a077-472c-b377-cca4a9230e1b');
Thanks Murali..I tried the approach of declaring a variable and then using Flatten and stringSplit to join..However I get the following error
Syntax error, unexpected symbol at or near 'flatteneduserids'
%declare REQUIRED_USER_IDS 'xxxxx,yyyyy,sssss' ;
inputData = load '$INPUT' USING PigStorage('|') AS (useriD:chararray,controllerAction:chararray,url:chararray,browserName:chararray,IsMobile:chararray,exceptionDetails:chararray,renderTime:int,serviceHostId:int,auditEventTime:chararray);
filteredInput = filter inputData by controllerAction is not null and auditEventTime is not null and serviceHostId is not null and renderTime is not null;
flatteneduserids = FLATTEN(STRSPLIT('$REQUIRED_USER_IDS',',')) AS (uid:chararray);
useridfilter = JOIN filteredInput BY useriD, flatteneduserids BY uid USING 'replicated';
so Now I tried another way of declaring flatteneduserids which results in the error Undefined alias: IN
flatteneduserids = FOREACH IN GENERATE FLATTEN(STRSPLIT('$REQUIREDUSERIDS',',')) AS (uid:chararray);
Had a similar use case. Tried the approach by declaring the constant value in %define and accessing the same inside IN clause, was not able to achieve the objective. (Refer : Declare a comma seperated string constant)
A thought worth contemplating ....
If the condition inside IN clause is a static/ reference/ meta kind of data, then would suggest to declare this in a static file. We can then read the data at run time and do an inner join with input data to retrieve the matching records.
input_data = LOAD '$INPUT' USING PigStorage('|') AS (user_id:chararray ...)
static_data = LOAD ... AS (req_user_id:chararray
required_data = JOIN input_data BY useriD, static_data BY req_user_id USING 'replicated';
required_data_fmt = -- project required fields.
I was not able to figure out how to do this in memory
So as per Murali's suggestion I added the user ids in a file..load the file and then do a join...that worked as expected for mr
I am trying to parse a log extract with multiple delimiters with sample data as below using pig
CEF:0|NetScreen|Firewall/VPN||traffic:1|Permit|Low| eventId=5
msg=start_time\="2015-05-20 09:41:38" duration\=0 policy_id\=64
My code is as below:
A = LOAD '/user/cef.csv' USING PigStorage(' ') as
(a:chararray,b:chararray,c:chararray,d:chararray,e:chararray,f:chararray,g:chararray);
B = FOREACH A GENERATE STRSPLIT(SUBSTRING(a, LAST_INDEX_OF(a,'|')+1, (int)SIZE(a)),'=',2),STRSPLIT(b,'=',2),STRSPLIT(c,'=',2),STRSPLIT(d,'=',2),STRSP LIT(e,'=',2),STRSPLIT(f,'=',2),STRSPLIT(g,'=',2);
C = FOREACH B GENERATE FLATTEN($0), FLATTEN($1), FLATTEN($2),FLATTEN($3),FLATTEN($4),FLATTEN($5);
D = FOREACH C GENERATE $2,flatten(STRSPLIT($4,'"',2)),flatten(STRSPLIT($5,'"',2)),$7,$9;
E = FOREACH D GENERATE (int)$0,(chararray)$2,(chararray)$3,(int)$5,(int)$6 as (a:int,b:chararray,c:chararray,D:int,E:int);
Now when i dump E,i get the error
grunt> 2015-05-25 04:06:48,092 [main] ERROR org.apache.pig.tools.grunt.Grunt
- ERROR 1031: Incompatable schema: left is
"a:int,b:chararray,c:chararray,D:int,E:int", right is ":int"
I am trying to cast the output of my flatten and strsplit operations into chararray and int.
Please let me know whether this can be done
Thank you for the help!
Your problem is how you use the as clause. Since you place the as after the sixth parameter, it assumes you are trying to specify that schema only for that sixth parameter. Therefore, you are assigning a schema of six fields to only one, hence the error.
Do it like this:
E = FOREACH D GENERATE (int)$0 as a:int,(chararray)$2 as b,(chararray)$3 as c,(int)$5 as d,(int)$6 as e;
However, you are casting 09:41:38" to an int, so it will give you another error once you change it. You need to check again how you are splitting the data.
In my humble opinion, you should try to split the files by their delimiter before processing them in Pig, and then load them with their delimiter and perform an union. If your data is too large, then forget this idea... But your code is going to get too messy if you have several delimiters in the same file.
A Pig newbie here. I have a relation A with multiple fields (f1,f2...). I want to quickly see all the distinct values that are there in each field.
Right now, I am doing this:
f1 = FOREACH A GENERATE f1;
f1 = DISTINCT f1;
dump f1;
I don't want to do this for each field. It is too elaborate. Is it possible instead to write some kind of a function in Pig to do this. I've looked at UDFs in the documentation, but I don't want to switch to another language like Java or Python. I think Pig is fine for what I am doing.
What you are looking for is a Macro. This is the equivalent to a function.
DEFINE MY_MACRO(relation,field) RETURNS selected_field_distinct {
selected_field = FOREACH $relation GENERATE $field;
$selected_field_distinct = DISTINCT selected_field;
};
A = LOAD 'input.txt' USING PigStorage(',') AS (f1:chararray, f2:chararray);
F1 = MY_MACRO(A,'f1');
F2 = MY_MACRO(A,'f2');
DUMP F1
DUMP F2
Please note that:
You have to declare the macro above the location where you use it.
You can also write your macro on a different file and import it to your script.
There is no way to use the command DUMP within the macro as described here.
A thought worth contemplating ....
If the values seen in f1 will not occur in f2 then you can try this approach. In this case we are performing DISTINCT only once.
f1 = FOREACH A GENERATE f1;
f2 = FOREACH A GENERATE f2;
...
f10 = FOREACH A GENERATE f10;
all_values = UNION f1,f2,..., f10;
uniq_values = DISTINCT all_values;
DUMP uniq_values;