Can I combine these 3 rewrite rules into 1? - .htaccess

Question

I'm having a brain fade and need some help please. I'm using 3 RewriteRules to accomplish something that I think should take just one:
RewriteRule ^([0-9]+)$ /bar/$1.html [R=301,L]
RewriteRule ^([0-9]+)(-*)$ /bar/$1.html [R=301,L]
RewriteRule ^([0-9]+)-([0-9]+)$ /bar/$1.html#$2 [R=301,NE,L]
I need to take the following URLs:
http://foo.com/100
http://foo.com/100-1
http://foo.com/200-
http://foo.com/1999
http://foo.com/1999-99
...and rewrite them like this:
http://foo.com/bar/100.html
http://foo.com/bar/100.html#1
http://foo.com/bar/200.html
http://foo.com/bar/1999.html
http://foo.com/bar/1999.html#99
What I have works but seems like a bit of a hack. is there a way to combine this all in to one rule?

Answer 1

I don't see a way to combine all three rules into a single rule, because the replacement structure is not always the same, with hash sometimes appearing and sometimes not appearing. But you can combine the first two rules:
RewriteRule ^([0-9]+)-?$ /bar/$1.html [R=301,L]
The second rule, which replaces with a hash symbol, can remain as is:
RewriteRule ^([0-9]+)-([0-9]+)$ /bar/$1.html#$2 [R=301,NE,L]

Answer 2

You can combine all 3 rules into one with this trick:
RewriteCond %{REQUEST_URI} ^/(\d+)-?(\d+)?$
RewriteCond %1#%2 ^(\d+)#$ [OR]
RewriteCond %1#%2 ^(\d+)(#\d+)$
RewriteRule ^ /bar/%1.html%2 [R=301,L,NE]
In the first condition, we match regex pattern that starts with a number followed by an optional hyphen and another optional number.
Next two conditions are using [OR] so only one will be true.
For URI /100, first condition will be true and 100 will be captured in %1 but %2 will be empty.
For URI /100-1, second condition will be true and 100 will be captured in %1 but %2 will be #1.