I'd use the cut operator here. The cut operator stops backtracking from occurring:

$_ = "1 1.0 3.547 92.34 343.2234";

while (/(?<![\d.])((?>\d+))(?!\.\d)/g) {
  print "$1\n";
}
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The OGRE would say (I'm paraphrasing): "make sure we're not preceded by a digit or a period, then, saving to $1, match (without backtracking) one or more digits, and then make sure we can't match a period and a digit." If we removed the cut operator, that \d+ could backtrack to say that in "123.456", the "12" part is found as an integer, which would be a false positive.

If you want, like mirod did, to match 1.0 as an integer, you would change this to:

/(?<![\d.])((?>\d+(?:\.0+)?))(?!\.\d)/g
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japhy -- Perl and Regex Hacker