TCL 正则表达式模式搜索 [英] TCL regexp pattern search

问题描述

我试图找到一个模式匹配如下abc(xxxx):efg(xxxx):xyz(xxxx) 其中 xxxx - [0-9] 个数字

I am trying to find a pattern match as below abc(xxxx):efg(xxxx):xyz(xxxx) where xxxx - [0-9] digits

我用过

set string "my string is abc(xxxx):efg(xxxx):xyz(xxxx)"
regexp abc(....):efg(....):xyz(....) $string result_str

它返回 0.有人可以帮忙吗?

it returns 0. Can anyone help?

推荐答案

你遇到的问题是 ( 和 ) 对 Tcl 中的正则表达式有特殊意义(以及许多其他 RE 引擎)，因为它们表示捕获子 RE.为了使字符正常"，它们必须用反斜杠转义，这意味着最好将正则表达式放在大括号中(因为反斜杠是通用的 Tcl 元字符).

The problem you've got is that ( and ) have special meaning to regular expressions in Tcl (and many other RE engines besides) in that they denote a capturing sub-RE. To make the characters "normal", they have to be escaped with a backslash, and that means that it's best to put the regular expression in braces (because backslashes are general Tcl metacharacters).

因此:

% set string "my string is abc(xxxx):efg(xxxx):xyz(xxxx)"
% regexp {abc\(....\):efg\(....\):xyz\(....\)} $string
1

如果你想还捕获那些括号的内容，你需要一个稍微复杂的 RE:

If you want to also capture the contents of those parentheses, you need a slightly more complex RE:

regexp {abc\((....)\):efg\((....)\):xyz\((....)\)} $string \
        all abc_bit efg_bit xyz_bit

请注意，那些 .... 序列总是精确匹配四个字符，但最好更具体一些.在每种情况下匹配任意数量的数字:

Note that those .... sequences always match exactly four characters, but it's better to be more specific. To match any number of digits in each case:

regexp {abc\((\d+)\):efg\((\d+)\):xyz\((\d+)\)} $string -> abc efg xyz

^{当使用 regexp 提取字符串的位时，使用 -> 作为整个字符串的(相当奇怪的)变量名是很常见的比赛;它看起来像是在说将提取的片段发送到这些变量".}

^{When using regexp to extract bits of a string, it's pretty common to use -> as a (rather strange) variable name for the whole string match; it looks mnemonically like it's saying "send the pieces extracted to these variables".}

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