我想在Spark Dataset中将整个列的大小写更改为小写
Desired Input
+------+--------------------+
|ItemID| Category name|
+------+--------------------+
| ABC|BRUSH & BROOM HAN...|
| XYZ|WHEEL BRUSH PARTS...|
+------+--------------------+
Desired Output
+------+--------------------+
|ItemID| Category name|
+------+--------------------+
| ABC|brush & broom han...|
| XYZ|wheel brush parts...|
+------+--------------------+
我尝试了
collectAsList()和toString()，这对于非常大的数据集来说是缓慢而复杂的过程。我还发现了一种“降低”方法，但是却不知道如何使它在dasaset中工作
请建议我一种简单或有效的方法来完成上述操作。提前致谢
最佳答案
使用lower中的org.apache.spark.sql.functions函数
例如:
df.select($"q1Content", lower($"q1Content")).show
输出。
+--------------------+--------------------+
| q1Content| lower(q1Content)|
+--------------------+--------------------+
|What is the step ...|what is the step ...|
|What is the story...|what is the story...|
|How can I increas...|how can i increas...|
|Why am I mentally...|why am i mentally...|
|Which one dissolv...|which one dissolv...|
|Astrology: I am a...|astrology: i am a...|
| Should I buy tiago?| should i buy tiago?|
|How can I be a go...|how can i be a go...|
|When do you use ...|when do you use ...|
|Motorola (company...|motorola (company...|
|Method to find se...|method to find se...|
|How do I read and...|how do i read and...|
|What can make Phy...|what can make phy...|
|What was your fir...|what was your fir...|
|What are the laws...|what are the laws...|
|What would a Trum...|what would a trum...|
|What does manipul...|what does manipul...|
|Why do girls want...|why do girls want...|
|Why are so many Q...|why are so many q...|
|Which is the best...|which is the best...|
+--------------------+--------------------+
关于java - 如何将整列的大小写更改为小写？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43500827/