string:contains?

Question whether a string contains a substring

string:contains?(STRING string
, STRING substring) : BOOL

string:contains?('hi there','hi')
#=> TRUE

string:contains?('amin','n')
#=> TRUE

string:contains?('SunSed Rocks 10',10)
#=> TRUE

# note: '' (empty string) as substring always returs true
string:contains?('hi there','')
#=> FALSE

# note: the match is case sensitive
string:contains?('my friend','Friend')
#=> FALSE