描述

Question

我正在努力让我的正则表达式工作2个小时...但只是头疼。

我想要的是：序列中的所有“c”（不是“查询：”而不是“Sbjct：”）

    Query: 1   atttatccttttggtcagaattttatatataagtattttttatttttctttggaccaaaa 60
               ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
    Sbjct: 1   atttatccttttggtcagaattttatatataagtattttttatttttctttggaccaaaa 60


    Query: 61  ttttatgcatcacattgtagcttttctgcaccacgccacatcacactacattttttctgt 120
               ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
    Sbjct: 61  ttttatgcatcacattgtagcttttctgcaccacgccacatcacactacattttttctgt 120

我得到/\b(?:(?!Sbjct)(?!Query)\w)+(c)/g但它只捕获每一行的最后一个“c”（我想要所有“c”）。

感谢您的帮助。

Answer 1

我认为你的意思是你想要任何一封信＆＃39; c＆＃39;在行标题中发现忽略 - 即：如果＆＃39; c＆＃39;在结肠左侧，它被忽略但是结肠后的所有c都要被捕获。你不能准确地说出捕获的内容 - 所以这就是我所提出的;

use v5.12;

while (<>) {
    say "Examining line $." ;
    next unless /:/g ;
    while (/ (c+) /gx)  {
        say "  Found \"$1\" at position ", pos ;
    }
}

# when fed the 8 lines above ...
Examining line 1
  Found "cc" at position 19
  Found "c" at position 27
  Found "c" at position 59
  Found "cc" at position 67
Examining line 2
Examining line 3
  Found "cc" at position 19
  Found "c" at position 27
  Found "c" at position 59
  Found "cc" at position 67
Examining line 4
Examining line 5
Examining line 6
  Found "c" at position 19
  Found "c" at position 22
  Found "c" at position 24
  Found "c" at position 32
  Found "c" at position 37
  Found "c" at position 40
  Found "cc" at position 43
  Found "c" at position 45
  Found "cc" at position 48
  Found "c" at position 50
  Found "c" at position 53
  Found "c" at position 55
  Found "c" at position 57
  Found "c" at position 60
  Found "c" at position 68
Examining line 7
Examining line 8
  Found "c" at position 19
  Found "c" at position 22
  Found "c" at position 24
  Found "c" at position 32
  Found "c" at position 37
  Found "c" at position 40
  Found "cc" at position 43
  Found "c" at position 45
  Found "cc" at position 48
  Found "c" at position 50
  Found "c" at position 53
  Found "c" at position 55
  Found "c" at position 57
  Found "c" at position 60
  Found "c" at position 68

请注意，对于数据行3，＆＃39; c＆＃39;未捕获位置4。

这是由于next unless /:/g行坚持＆＃39;：＆＃39;在任何“c”被采取之前。 /x打开＆＃34;扩展模式＆＃34;在正则表达式中使用空格的正则表达式更加清晰。当使用/g - 全局匹配选项时 - 可以将正则表达式置于while循环中，它将从上次成功搜索的位置开始重复搜索目标。

Answer 2

描述

如果你是regex replace命令的全局选项，那么这个正则表达式将执行以下操作：

找到第一个c后面的字符串中的每个:（分号后面跟一个空格）
假设字符串
捕获每个c，以便可以替换
允许字符串包含多行
如果第一行以expect:开头，则忽略整行上的所有c
因为这是Javascript，所以不能使用负面的lookbehind

<强>正则表达式

匹配：((?:(?:expect:(?:(?!\r|\n).)*))?(?:(?:\r|\n|\A)+[^:]+:.*?)?)(c)

替换为：$1$2

解释

Regular expression visualization

NODE                     EXPLANATION
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
----------------------------------------------------------------------
      (?:                      group, but do not capture:
----------------------------------------------------------------------
        expect:                  'expect:'
----------------------------------------------------------------------
        (?:                      group, but do not capture (0 or more
                                 times (matching the most amount
                                 possible)):
----------------------------------------------------------------------
          (?!                      look ahead to see if there is not:
----------------------------------------------------------------------
            \r                       '\r' (carriage return)
----------------------------------------------------------------------
           |                        OR
----------------------------------------------------------------------
            \n                       '\n' (newline)
----------------------------------------------------------------------
          )                        end of look-ahead
----------------------------------------------------------------------
          .                        any character
----------------------------------------------------------------------
        )*                       end of grouping
----------------------------------------------------------------------
      )                        end of grouping
----------------------------------------------------------------------
    )?                       end of grouping
----------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
----------------------------------------------------------------------
      (?:                      group, but do not capture (1 or more
                               times (matching the most amount
                               possible)):
----------------------------------------------------------------------
        \r                       '\r' (carriage return)
----------------------------------------------------------------------
       |                        OR
----------------------------------------------------------------------
        \n                       '\n' (newline)
----------------------------------------------------------------------
       |                        OR
----------------------------------------------------------------------
        \A                       the beginning of the string
----------------------------------------------------------------------
      )+                       end of grouping
----------------------------------------------------------------------
      [^:]+                    any character except: ':' (1 or more
                               times (matching the most amount
                               possible))
----------------------------------------------------------------------
      :                        ':'
----------------------------------------------------------------------
      .*?                      any character (0 or more times
                               (matching the least amount possible))
----------------------------------------------------------------------
    )?                       end of grouping
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  (                        group and capture to \2:
----------------------------------------------------------------------
    c                        'c'
----------------------------------------------------------------------
  )                        end of \2
----------------------------------------------------------------------

粗略的Javascript示例

请注意，为了便于阅读此示例，我使用$1_$2_作为替换字符串而不是$1$2

<script type="text/javascript">
  var re = /((?:(?:expect:(?:(?!\r|\n).)*))?(?:(?:\r|\n|\A)+[^:]+:.*?)?)(c)



/;
  var sourcestring = "source string to match with pattern";
  var replacementpattern = "$1_$2_";
  var result = sourcestring.replace(re, replacementpattern);
  alert("result = " + result);
</script>

结果字符串

请注意，为了便于阅读此示例，我使用$1_$2_作为替换字符串而不是$1$2

Expect: 61 ttttatgcatcacattgtagcttttctgcaccacgccacatcacactacattttttctgt 120 
Query: 61 ttttatg_c_at_c_a_c_attgtag_c_tttt_c_tg_c_a_c__c_a_c_g_c__c_a_c_at_c_a_c_a_c_ta_c_atttttt_c_tgt 120 
Sbjct: 61 ttttatg_c_at_c_a_c_attgtag_c_tttt_c_tg_c_a_c__c_a_c_g_c__c_a_c_at_c_a_c_a_c_ta_c_atttttt_c_tgt 120

现场演示

http://fiddle.re/0qcuea

Answer 3

所以只是为了尝试简化一些事情而不是疯狂地向前看/在正则表达式之后，最好只用空格分割线，抓住包含DNA字符串的第n个元素然后简单

dna.replace('c', 'spanny goodness')

（抱歉。电话接听......）

捕获所有l个字母并排除单词

3 个答案:

描述

解释