我想从包含单词列表的DataFrame转换为DataFrame,每个单词都在自己的行中 .
如何在DataFrame中的列上进行爆炸?
下面是我的一些尝试示例,您可以在其中取消注释每个代码行并获取以下注释中列出的错误 . 我在Python 2.7中使用PySpark和Spark 1.6.1 .
from pyspark.sql.functions import split, explode
DF = sqlContext.createDataFrame([('cat \n\n elephant rat \n rat cat', )], ['word'])
print 'Dataset:'
DF.show()
print '\n\n Trying to do explode: \n'
DFsplit_explode = (
DF
.select(split(DF['word'], ' '))
# .select(explode(DF['word'])) # AnalysisException: u"cannot resolve 'explode(word)' due to data type mismatch: input to function explode should be array or map type, not StringType;"
# .map(explode) # AttributeError: 'PipelinedRDD' object has no attribute 'show'
# .explode() # AttributeError: 'DataFrame' object has no attribute 'explode'
).show()
# Trying without split
print '\n\n Only explode: \n'
DFsplit_explode = (
DF
.select(explode(DF['word'])) # AnalysisException: u"cannot resolve 'explode(word)' due to data type mismatch: input to function explode should be array or map type, not StringType;"
).show()
请指教
2 回答
explode
和split
是SQL函数 . 两者都在SQLColumn
上运行 .split
将Java正则表达式作为第二个参数 . 如果你想在任意空格上分隔数据,你需要这样的东西:要拆分空格并删除空行,请添加
where
子句 .