修改：原来有“p=name [i]其实和p = name + i没有任何区别”一句，是不对的，name [i]是数组，其中name可以作为只读指针来看待，那么应该是*p = * (name + i)。name [i]相当于对指针 这问题提的真好，理解这个问题了以后，对C语言指针的概念也就掌握了，而C语言最重要的就是指针。题主这重点抓的真到位. The p tag is a p aragraph, and as such, it is a block element (as is, for instance, h1 and div), whereas span is an inline element (as, for instance, b and a) Block elements by default create some whitespace above and below themselves, and nothing can be aligned next to them, unless you set a float attribute to them. Unicode scripts, blocks, categories and binary properties are written with the \p and \P constructs as in Perl. \p prop matches if the input has the property prop, while \P prop does not match if the input has that property. And then Z is the name of a class (collection, set) of characters. In this case, it's abbreviation of Separator. The Unicode property \p L — shorthand for \p Letter will match any kind of letter from any language. Therefore, \p Lu will match an uppercase letter that has a lowercase variant. Mac开机时按住Command+Option+P+R 键，重置Pram和Nvram，从而达到恢复系统速度的方法真的有效么？ 微博上看来的「重如感觉系统越来越慢，或者是iTunes怎么都无法和iOS设备同步。 这时候你可以重置下Mac的Pram和Nvram。 方法是1、彻底关闭电… 显示全部 关注者 344 Learn how to adjust the height of a paragraph in HTML using CSS properties and techniques on Stack Overflow. What does P stand for? I could not find any hint in the official documentation. I would love to get ideas about how to help my students remember this syntax. Knowing what P does stand for (or might stand for) would be useful. (?P category_slug ) creates a match group named category_slug. The regex itself matches a string starting with category/ and then a mix of alphanumeric characters, the dash - and the underscore _, followed by a trailing slash. What is the difference between <p and <div ? Can they be used interchangeably? What are the applications? x is Unsigned hexadecimal integer ( 32 Bit ) p is Pointer address See printf on the C++ Reference. Even if both of them would write the same, I would use %p to print a pointer.