Regular expression system tutorial (2)_PHP tutorial
2. The history of regular expressions
The "ancestors" of regular expressions can be traced back to early research on how the human nervous system works. Two neurophysiologists, Warren McCulloch and Walter Pitts, developed a mathematical way to describe these neural networks.
In 1956, a mathematician named Stephen Kleene published a paper titled "Representation of Neural Network Events" based on the early work of McCulloch and Pitts, which introduced regular expressions. concept. Regular expressions are used to describe expressions that he calls "the algebra of regular sets," hence the term "regular expression."
It was subsequently discovered that this work could be applied to some early research using the computational search algorithms of Ken Thompson, the primary inventor of Unix. The first practical application of regular expressions was the qed editor in Unix.
As they say, the rest is history as we all know. Regular expressions have been an important part of text-based editors and search tools ever since.
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