First I have checked the following code:

0x11

# 17

0x1.1

# 17I seemed that GNU R drops the decimal point. So I have checked notation with exponent being power of 2 (as in Java):

0x1.1p0

# 1.0625

0x1.1p4

# 17Now decimal point is correctly taken into account so I have checked further.

In the notation without exponent part GNU R just discards decimal points as in this example:

0x111

# 273

0x1.1.1

# 273

0x....1....1....1

# 273However, in notation with exponent last decimal point is taken into consideration and all earlier decimal points are ignored:

0x11.1p0

# 17.0625

0x1.1.1p0

# 17.0625

0x....1....1....1p0

# 17.0625In summary - handling of hexadecimal literals in GNU R is nonstandard and at least for me - unexpected.

Post to R-devel - this looks like a parser bug and if it is then it would be nice if it's fixed in time for the R 3.0.0 release.

ReplyDelete/Henrik Bengtsson