How to select the columns of a dataframe based on a vector of strings, matching for exact coincidence?

I have a dataframe with the followign column names:

NewYork_10
NewYork_20
NewYork3_10
NewYork3_20
NewYork4_10
NewYork4_20
HongKong_10
HongKong_20
SanFrancisco_10
SanFrancisco_20

And I have a vector:

list <- c("NewYork", "SanFrancisco")

I want a script that creates a new dataframe, selecting those columns that have the exact same string before the underscore.
In the example given above, you would get a new dataframe with the following columns.
NewYork_10
NewYork_20
SanFrancisco_10
SanFrancisco_20

I did several tries with grep:

dplyr::select(matches(list_cities))

dplyr::select(matches(paste0(list_cities), "_"))

And even using anchors for a vector, which I’m not sure is possible.

dplyr::select(matches(paste0("^",list_cities, "_.*")))

But in every case it’s capturing all the values of the vector that start with the given substring.

>Solution :

We can also use matches

df %>%
    select(matches("(NewYork)|(SanFrancisco)_.*")