The ending between lines is data, not decoration. Two machines can disagree about it, and that disagreement shows up as broken parsing.
About 1 min of reading
Check endings in text.
Unix style shown.
Before you run it, say out loud what it will print. Then open the answer.
Windows style shown.
Before you run it, say out loud what it will print. Then open the answer.
Rows across both styles.
Before you run it, say out loud what it will print. Then open the answer.
Endings counted.
Before you run it, say out loud what it will print. Then open the answer.
Read the first example one line at a time. A line that prints shows what appears on screen; the rest set things up quietly.
A file holds the ending bytes you wrote. Nothing converts them for you, so a mixed file is a mixed file.
Read with splitlines so either style works, and write one style you state. That combination survives a move between machines.
print(repr("a\nb"))
print(repr("a\r\nb"))One newline is unix style. Carriage return plus newline is windows style. Both are real files.
text = "a\r\nb\nc"
print(len(text.splitlines()))splitlines handles both styles. Splitting on a bare newline leaves a stray character.
text = "a\r\nb"
parts = text.split("\n")
print(repr(parts[0]))Splitting on newline only leaves the carriage return stuck to the first part.
out = "\n".join(["a", "b"])
print(repr(out))Build with newline and write in binary or name the ending. Then the file is predictable.
text = "a\nb\nc"
print(text.count("\n"))Two endings for three lines. The last line may have none, which is legal.
text = "a"
print(len(text.splitlines()))One line, no ending. A reader that demands an ending calls this truncated.
Each one is defined here on this site. Open the entry for the full definition and the other words it points at.