A sequence like this will often be written either in square brackets [1, 2, 3, 4] (called a list) or in parentheses (1, 2, 3, 4) (a tuple).

• 像这样的序列常常被放在中括号里[1,2,3,4]（叫做一个列表）或者在圆括号里(1,2,3,4)（一个元组）。