Adding a string between some pattern in R

I would like to add the string "AND" between the words "STREET" and "HENRY" into the following string:

WEST 156 STREET HENRY HUDSON PARKWAY

So that it reads WEST 156 STREET AND HENRY HUDSON PARKWAY. Essentially, I am trying to geocode intersections so I would like to be able to add "AND" between street types (AVENUE, STREET, BLVD, etc.) and whatever word comes after that to create the intersection like I specified above.

Here are a couple more examples (just made up):

strings = c("WEST 135TH AVE BROADWAY", # want WEST 135TH AVE AND BROADWAY,
"SUNSET BLVD MAIN ST", # SUNSET BLVD AND MAIN ST
"W 45TH ST LAKESHORE BLVD", #...
"HIGH ST BROAD ST") # ...

I would greatly appreciate any help! I am somewhat familiar with regular expressions, but I am not familiar with how to insert another word in this manner.

Solution 1:

capture the words as a group and replace with backreference (\\1) along with the substring "AND". For the third and fourth strings, as it is at the end of the string, it wouldn't replace as we used \\s+ (one or more spaces)

sub("(AVENUE|AVE|STREET|BLVD)\\s+", "\\1 AND ", strings)

-output

[1] "WEST 135TH AVE AND BROADWAY" "SUNSET BLVD AND MAIN ST"    
[3] "W 45TH ST LAKESHORE BLVD"    "HIGH ST BROAD ST"