Data engineer Interview Questions

2years

I have no experience

Map>> ret = mappy.entrySet().stream(). collect( Collectors.groupingBy( x -> x.getValue())); Map result = ret.entrySet().stream().collect ( Collectors.toMap( x -> x.getKey(), y -> y.getValue().stream().map( p -> p.getKey()).collect(Collectors.joining(",")))); System.out.println(result);

d = {'A': 10, 'B': 5, 'C': 5, 'D': 12, 'E': 3} d2 = {} for k, v in d.items(): if d2.get(v, '') == '': d2[v] = k else: d2[v] = "{}, {}".format(d2[v], k) for k, v in d2.items(): print "{}: {}".format(k, v)

Mysql is a relational database (RDBMS) while Oracle database is a multi model database which means it supports document, graphs, relational and key value pair within a single database.

hadoop for fs hadoop 2 for dfs

Simple answers

write comma seperated table name

The interviewer is trying to see if you know of Pythons list comprehension rather than running nested loops.