x<- c( "*NAME ALPHA PHRASE1 BLA BLA TEXT 81249" , "*NAME BETA PHRASE1 BLA BLA 81229" , "*NAME GAMMA PHRASE2 BLA BLA TEXT 85129" , "*NAME DELTA PHRASE3 BLA BLA 86129" , "*NAME EPSILON PHRASE2 BLA BLA 81729" )
context <- c( "PHRASE1" , "PHRASE2" , "PHRASE3" )
pattern <- paste0( "\\ *\\ K.*?(?=\\ s+(?:" , paste( context, collapse= "|" ) , "))" )
regmatches( x, regexpr( pattern, x, perl= TRUE) )
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