How to search for multiple words in the same string using R

问题

I'm trying to extract tweets that contains 2-3 words in the same tweet.

Below is my code where I'm extracting tweets that matches a particular word. But I need to extract tweets that matches multiple words in the same tweet.

search.string <- "#DeltaAirlines"
no.of.tweets<-1500
tweets <- unique(searchTwitter(search.string, n=no.of.tweets, lang="en"))

I've tried using AND in the search.string function but its returning me an empty list even though there are tweets that contain those 2-3 words.

来源：https://stackoverflow.com/questions/37684179/how-to-search-for-multiple-words-in-the-same-string-using-r