Transcranial Doppler (TCD), first described in 1982 [1], is a noninvasive ultrasound (US) study that involves the use of a low-frequency (â¤2 MHz) transducer probe to insonate the basal cerebral arteries through relatively thin bone windows.
Details. as.character and is.character are generic: you can write methods to handle specific classes of objects, see InternalMethods. Further, for as.character the default method calls as.vector, so dispatch is first on methods for as.character and then for methods for as.vector.
Create a character vector with more than one element. To create a character vector with more than one element, use the combine function, c() : Notice that this time, R tells you that your vector has length 2 and that the first element has five characters and the second element has six characters. 1  Add a Comment.2  Print.o create a character vector with more than one element, use the combine function, c() : Notice that this time, R tells you that your vector has length 2 and that the first element has five characters and the second element has six characters. 1  Add a Comment.