CODEWITHSUNDEEP
hadoopmapreduceapache-pigbigdata
user182944
user182944

Reputation: 8067

AVG on grouped data throwing ERROR 1046:Use an Explicit Cast

I have a MAP of data in a txt file:

[age#27,height#5.8]
[age#25,height#5.3]
[age#27,height#5.10]
[age#25,height#5.1]

I want to display the average height for each group of age.

This is the LAOD statement:

records = LOAD '~/Documents/Pig_Map.txt' AS (details:map[]);
records: {details: map[]}

Then I grouped the data based on age:

group_data = GROUP records BY details#'age';
group_data: {group: bytearray,records: {(details: map[])}}

for accessing the details I did a FLATTEN like this (NOT SURE IF I NEED THIS STEP):

flatten_records = FOREACH group_data GENERATE group,FLATTEN(records);
flatten_records: {group: bytearray,records::details: map[]}

DUMP flatten_records this give me the below output:

(25,[height#5.1,age#25])
(25,[height#5.3,age#25])
(27,[height#5.10,age#27])
(27,[height#5.8,age#27])

Now I want to get the average height; I tried this:

display_records = FOREACH flatten_records GENERATE group,AVG(records.details#'height');

The error is:

<line 10, column 57> Multiple matching functions for org.apache.pig.builtin.AVG with input schema: ({{(bytearray)}}, {{(double)}}). Please use an explicit cast.

Please advice.

Upvotes: 0

Views: 321

Answers (1)

Sivasakthi Jayaraman
Sivasakthi Jayaraman

Reputation: 4724

Can you try this?

records = LOAD '~/Documents/Pig_Map.txt' AS (details:map[]);
records1 = FOREACH records GENERATE details#'age' AS age,details#'height' AS height;
group_data = GROUP records1 BY age;
display_records = FOREACH group_data GENERATE group,AVG(records1.height);
dump display_records;

Output:

(25,5.199999999999999)
(27,5.449999999999999)

Upvotes: 2

Related Questions