英文:
Match after a string and whitespaces?
问题
I can provide the translated code portion without any additional content:
import re
proc extractColor(input: string, key: string): string =
var regex = compileRegex(key & "=\s*([^\n\r]+)")
if regex.search(input):
return regex.match(input).group(1)
else:
return ""
let input = """
COLOR1= Light Blue
COLOR2= Dark Red
"""
let color1 = extractColor(input, "COLOR1")
let color2 = extractColor(input, "COLOR2")
echo color1
echo color2
This Nim code defines a extractColor procedure that extracts the color value associated with a given key from the input string while removing any leading whitespace. The regular expression used is compatible with the PCRE (Perl-Compatible Regular Expressions) library, which you mentioned is used in the Nim programming language.
英文:
If I have the following line, for example:
COLOR1= Light Blue
COLOR2= Dark Red
I'm looking for a regex that if I pass the string "COLOR1=" to it, it will match only "Light Blue", without all the whitespace before "Light". The same if I pass "COLOR2=", which should match only "Dark Red".
I tried (?<=COLOR1=)[^.]*, but it doesn't remove whitespace after the "=" and before the first non-empty character, and has problems with newlines.
EDIT: I am using the Nim programming language, which compiles to C code. Regular expressions in this language are based on PCRE (Perl-Compatible Regular Expressions) C library.
答案1
得分: 1
你可以使用 \K 来在匹配关键字、等号和后续空白字符之后重置匹配：
COLOR1=\s*\K.*
演示：https://regex101.com/r/zSwjKO/1
英文:
You can use \K to reset the match after matching the key, the equal sign and any subsequent whitespaces:
COLOR1=\s*\K.*
答案2
得分: 1
尝试匹配正则表达式
(?m)^COLOR2=\s*(.+)
如果有匹配，捕获组1将包含所需的字符串。
该表达式包含以下元素。
(?m) # 设置多行标志
^ # 匹配行的开头
COLOR2= # 匹配字面文本
\s* # 匹配零个或多个空白字符
( # 开始捕获组1
.+ # 匹配除换行符之外的一个或多个字符
) # 结束捕获组1
多行标志 m（在 (?m) 中）使 ^ 匹配行的开头和结尾。在某些编程语言中，多行标志的设置方式可能不同。在Ruby中，不需要该标志，因为 ^ 匹配行的开头（而 \A 匹配字符串的开头）。
英文:
Attempt to match the regular expression
(?m)^COLOR2=\s*(.+)
If there is a match capture group 1 will hold the desired string.
The expression has the following elements.
(?m) # set the multiline flag
^ # match the beginning of a line
COLOR2= # match literal
\s* # match zero or more whitespace chars
( # begin capture group 1
.+ # match one or more chars other than line terminators
) # end capture group 1
The multiline flag m (in (?m)) causes ^ to match the start and end of a line. In some languages the multiline flag is set differently. In Ruby there is no need for that flag as ^ matches the beginning of a line (and \A matches the beginning of the string).
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