Portable calculator for an array calculation

A portable calculator comprising:

• an input key group for inputting an arithmetic expression, said input key group including a plurality of first keys each for inputting a decimal digit constituting an operand as combined or alone, a plurality of second keys for inputting an operator and at least one third key for inputting a separating symbol;
• a first memory section, operatively connected to said input key group, for storing an arithmetic expression input by said input key group;
• an array detecting section, operatively connected to said first memory section, for identifying each operand included in said arithmetic expression as a single operand or one of a plurality of elements of an array comprising a group of operands, each successive two of said plurality of elements of said array sandwiching a separating symbol and sandwiching no operator;
• a second memory section, operatively connected to said array detecting section, for storing each array identified by said array detecting section;
• an arithmetic executing section, operatively connected to said first memory section and second memory section, for executing an arithmetic operation between corresponding elements of a plurality of arrays or between each of said plurality of elements of each array and each single operand.