Return to Answer

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String, NullRecords -> True]

On my system this is more than three times as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}], NullRecords -> True]

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String, NullRecords -> True]

On my system this is more than three times as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}], NullRecords -> True]

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String]

On my system this is more than three times as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}]]

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String, NullRecords -> True]

On my system this is more than three times as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}], NullRecords -> True]

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String]

On my system this is more than twice as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}]]

Lots of answers, but none of them leveraging this, so here is another.

null[_String] := Null

Length @ ReadList["data.txt", null @ String]

On my system this is more than three times as fast as Rolf Mertig's CountLines, and a lot more concise as well.

If even one Null for every record is too much memory usage then read in blocks of e.g. 1000:

num[Longest[x__String], ___] := Length @ {x}

Tr @ ReadList["data.txt", num @@ Table[String, {1000}]]