In Scala, how to read a simple CSV file having a header in its first line?
The task is to look for a specific field (by it's number in line) value by a key field value in a simple CSV file (just commas as separators, no field-enclosing quotes, never a comma inside a field), having a header in its first line.
User uynhjl has given an example (but with a different character as a separator):
val src = Source.fromFile("/etc/passwd")
val iter = src.getLines().map(_.sp开发者_如何学Pythonlit(":"))
// print the uid for Guest
iter.find(_(0) == "Guest") foreach (a => println(a(2)))
// the rest of iter is not processed
src.close()
the question in this case is how to skip a header line from parsing?
You can just use drop
:
val iter = src.getLines().drop(1).map(_.split(":"))
From the documentation:
def drop (n: Int) : Iterator[A]
: Advances this iterator past the first n elements, or the length of the iterator, whichever is smaller.
Here's a CSV reader in Scala. Yikes.
Alternatively, you can look for a CSV reader in Java, and call that from Scala.
Parsing CSV files properly is not a trivial matter. Escaping quotes, for starters.
First I read the header line using take(1)
, and then the remaining lines are already in src
iterator. This works fine for me.
val src = Source.fromFile(f).getLines
// assuming first line is a header
val headerLine = src.take(1).next
// processing remaining lines
for(l <- src) {
// split line by comma and process them
l.split(",").map { c =>
// your logic here
}
}
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