What language structures does php have?

#1. What is language structure?

php language keyword, part of the language syntax, cannot be defined by the user or added to the language library, it may or may not have variables and return values

2. The reason why the language structure executes quickly (Recommended learning: PHP video tutorial)

The function must first be parsed into a language structure by the php parser (Zend engine) , Therefore, the function has one more layer of parser than the language structure, and the speed is slower.

3. What are the language structures in PHP?

echo、print、die、isset、unset、include、require、array、list、empty

4. How to determine whether it is a language structure or a function?

function_exists或者php --rf

5. The difference between language structures and functions:

Language structures are faster than corresponding functions

Because they are language keywords , The error cannot be processed again

The language structure cannot be disabled in the configuration item php.ini, the function can

The language structure cannot be used as a callback function, the function can

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