


Online communication is an interview question for PHP programmers at Tencent
11.你用什么方法检查PHP脚本的执行效率(通常是脚本执行时间)和数据库SQL的效率(通常是数据库Query时间),并定位和分析脚本执行和数据库查询的瓶颈所在? 1.脚本执行时间,启用xdebug,使用WinCacheGrind分析。 2.数据库查询,mysql使用EXPLAIN分析查询,启用slow query log记录慢查询。 PHP LAMP Engineer Test Paper Question 1 What does echo count ("123") ?> print out? A) 3 B) False C) Null D) 1 E) 0 Question 2 Which of the following snippets prints a representation of 42 with two decimal places? A) printf("%.2dn", 42); B) printf("%1.2fn", 42); C) printf("%1.2un", 42); Question 3 Given $text = 'Content-Type: text/xml'; Which of the following prints 'text/xml'? A) print substr($text, strchr($text, ':')); B) print substr($text, strchr($text, ':') + 1); C) print substr($text, strpos($text, ':') + 1); D) print substr($text, strpos($text, ':') + 2); E) print substr($text, 0, strchr($text, ':') Question 4 What is the value of $a?
A) True B) False Question 5 What is the value of $result in the following PHP code?
Answer: NULL Question 6 The code below ___________ because ____________.
A) will work, class definitions can be split up into multiple PHP blocks. B) will not work, class definitions must be in a single PHP block. C) will not work, class definitions must be in a single file but can be in multiple PHP blocks. D) will work, class definitions can be split up into multiple files and multiple PHP blocks. Question 7 When turned on, ____________ will _________ your script with different variables from HTML forms and cookies. A) show_errors, enable B) show_errors, show C) register_globals, enhance D) register_globals, inject Question 8 What will be the output of the following PHP code:
Answer: 1 Question 9 What is the best all-purpose way of comparing two strings? A) Using the strpos function B) Using the == operator C) Using strcasecmp() D) Using strcmp() Question 10 What is the difference between "print()" and "echo()"? Answer: print is a function,echo is a language construct |

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JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

Article discusses late static binding (LSB) in PHP, introduced in PHP 5.3, allowing runtime resolution of static method calls for more flexible inheritance.Main issue: LSB vs. traditional polymorphism; LSB's practical applications and potential perfo

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