pyspark使用s3中的regex/glob选择文件子集 [英] pyspark select subset of files using regex/glob from s3
问题描述
我有一个数字文件,每个文件按日期在Amazon S3上按日期(date=yyyymmdd)
分隔.这些文件可以追溯到6个月,但我想将脚本限制为仅使用最近3个月的数据.我不确定我是否可以使用正则表达式执行类似sc.textFile("s3://path_to_dir/yyyy[m1,m2,m3]*")
I have a number files each segregated by date (date=yyyymmdd)
on amazon s3. The files go back 6 months but I would like to restrict my script to only use the last 3 months of data. I am unsure as to whether I will be able to use regular expressions to do something like sc.textFile("s3://path_to_dir/yyyy[m1,m2,m3]*")
其中m1,m2,m3代表我要使用的当前日期起的3个月.
where m1,m2,m3 represents the 3 months from the current date that I would like to use.
一个讨论还建议使用类似sc.textFile("s3://path_to_dir/yyyym1*","s3://path_to_dir/yyyym2*","s3://path_to_dir/yyyym3*")
的方法,但这似乎对我不起作用.
One discussion also suggested using something like sc.textFile("s3://path_to_dir/yyyym1*","s3://path_to_dir/yyyym2*","s3://path_to_dir/yyyym3*")
but that doesn't seem to work for me.
sc.textFile( )
是否使用正则表达式?我知道您可以使用全局表达式,但是不确定如何将上述情况表示为全局表达式?
Does sc.textFile( )
take regular expressions? I know you can use glob expressions but I was unsure how to represent the above case as a glob expression?
推荐答案
对于第一个选择,使用花括号:
For your first option, use curly braces:
sc.textFile("s3://path_to_dir/yyyy{m1,m2,m3}*")
第二种选择是,您可以将每个单独的glob读入RDD,然后将这些RDD合并为一个:
For your second option, you can read each single glob into an RDD and then union those RDDs into a single one:
m1 = sc.textFile("s3://path_to_dir/yyyym1*")
m2 = sc.textFile("s3://path_to_dir/yyyym2*")
m3 = sc.textFile("s3://path_to_dir/yyyym3*")
all = m1.union(m2).union(m3)
您可以将globs与sc.textFile
一起使用,但不能与完整的正则表达式一起使用.
You can use globs with sc.textFile
but not full regular expressions.
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