Read

Read[stream] reads one expression from an input stream and returns the expression.

Read[stream, type] reads one object of the specified type.

Read[stream, {type1, type2, …}] reads a sequence of objects of the specified types.

Examples

Read from a stream:

stream = OpenRead["data.txt"];
Read[stream]
Close[stream]

Read specific type:

Read[stream, Number]

Please visit the official Wolfram Language Reference for more details.