Gawk datatypes

Text

first_name="joe"
last_name="george"
length("george")  # 6

# concatenation
full_name=first_name""last_name  # joegeorge

# split string
num_tokens = split("this is my string", a, " ")
a[1] = "this"
a[2] = "is"

Numbers

integer=1
float=1.1

Arrays

Arrays are 1-indexed in awk.
awk cannot tell the size of an already created array.