Why are multiple function parameters followed by half square brackets in the php manual? What are the meanings of these parentheses? I have always had this question. google and Baidu have no answer. I don't know if anyone can give me a answer. Thanks for the fact that many function parameters in the php manual are followed by half square brackets? What are the meanings of these parentheses?
I have always had this question. google and Baidu have no answer. I don't know if anyone can give me a answer.
Thanks
Reply content:
Why are multiple function parameters followed by half square brackets in the php manual? What are the meanings of these parentheses?
I have always had this question. google and Baidu have no answer. I don't know if anyone can give me a answer.
Thanks
Array array_filter (array $ array [, callable $ callback [, int $ flag = 0])
You mean$ CallbackAnd$ FlagThe brackets indicate that these parameters are optional.
