如何在scala中對相似的列值進行分組？

Question

欲組列值採用階，例如

sunny,hot,high,FALSE,no 
sunny,hot,high,TRUE,no 
overcast,hot,high,FALSE,yes 
rainy,mild,high,FALSE,yes 
rainy,cool,normal,FALSE,yes 
overcast,cool,normal,TRUE,yes 

我想要的結果爲，

對於IST柱.........

IST組

sunny,hot,high,FALSE,no 
sunny,hot,high,TRUE,no 

IIND組

overcast,hot,high,FALSE,yes 
overcast,cool,normal,TRUE,yes 

IIIrd組

rainy,mild,high,FALSE,yes 
rainy,cool,normal,FALSE,yes 

對於IIND柱.........

IST組

hot,high,FALSE,no 
hot,high,TRUE,no 
hot,high,FALSE,yes 

IIND組

cool,normal,FALSE,yes 
cool,normal,TRUE,yes 

一世IIrd組

mild,high,FALSE,yes 

同樣高達倒數第二列中的所有列............

Answer 1

使用Seq.groupBy方法。

val data = Seq(("sunny", "hot", "high", "FALSE", "no"), 
    ("sunny", "hot", "high", "TRUE", "no"), 
    ("overcast", "hot", "high", "FALSE", "yes"), 
    ("rainy", "mild", "high", "FALSE", "yes"), 
    ("rainy", "cool", "normal", "FALSE", "yes"), 
    ("overcast", "cool", "normal", "TRUE", "yes")) 

val byFirst = data.groupBy(_._1) 

結果：

Map(
    overcast -> List((overcast,hot,high,FALSE,yes), (overcast,cool,normal,TRUE,yes)), 
    rainy -> List((rainy,mild,high,FALSE,yes), (rainy,cool,normal,FALSE,yes)), 
    sunny -> List((sunny,hot,high,FALSE,no), (sunny,hot,high,TRUE,no)))