1. An associative searching system for searching a data input stream of text words for the occurrence of selected key words of interest, each text word including at least one character; comprising a plurality of key memories addressable in parallel for containing key words at predetermined positions; a word register means for receiving each text word of the data input stream; means for simultaneously comparing each text word one character at a time with the key words at a selected key memory address in all said plurality of addressable key memories; a word length register coupled to said word register means for determining and storing information indicative of the number of characters of each text word stored in said word register means; and an address generating means for generating said selected key memory address for each input text word from said word register means to indicate the address of key memories to insure comparison of each text word with key words of an identifiable likeness with respect to certain characters, said address generating means including further memory means containing certain predetermined information therein for indicating which certain bits are to be segregated from other bits by specific bit location in said text words, and said memory means being addressable by the total number of characters therein, and said address generating means including logic means responsive to said word length register for segregating bits from each text word in accordance with said further memory means to determine the key memory address corresponding to that text word.