我有一個疑問涉及到在PHP正則表達式。一個正則表達式使用php
$content = "START FIRST AAA SECOND AAA"
$content_first = preg_replace('/START(.*)AAA/', 'REPLACED_STRING', $content);
//$content_first == "REPLACED_STRING"
$content_second = preg_replace('/START(.*?)AAA/', 'REPLACED_STRING', $content);
//$content_second == "REPLACED_STRING SECOND AAA"
爲什麼$ content_second和$ content_first不一樣? ''的目的是什麼?在正則表達式?我有以下正則表達式(真正廣泛),我想修改它,所以它取代了一個字符串中的所有網址,而不是由第一個停止,但我無法(它只是發現字符串中的第一個URL ):
$url_pattern = '/# Rev:20100913_0900 github.com\/jmrware\/LinkifyURL
# Match http & ftp URL that is not already linkified.
# Alternative 1: URL delimited by (parentheses).
(\() # $1 "(" start delimiter.
((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+) # $2: URL.
(\)) # $3: ")" end delimiter.
| # Alternative 2: URL delimited by [square brackets].
(\[) # $4: "[" start delimiter.
((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+) # $5: URL.
(\]) # $6: "]" end delimiter.
| # Alternative 3: URL delimited by {curly braces}.
(\{) # $7: "{" start delimiter.
((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+) # $8: URL.
(\}) # $9: "}" end delimiter.
| # Alternative 4: URL delimited by <angle brackets>.
(<|&(?:lt|\#60|\#x3c);) # $10: "<" start delimiter (or HTML entity).
((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]+) # $11: URL.
(>|&(?:gt|\#62|\#x3e);) # $12: ">" end delimiter (or HTML entity).
| # Alternative 5: URL not delimited by(), [], {} or <>.
( # $13: Prefix proving URL not already linked.
(?:^ # Can be a beginning of line or string, or
| [^=\s\'"\]] # a non-"=", non-quote, non-"]", followed by
) \s*[\'"]? # optional whitespace and optional quote;
| [^=\s]\s+ # or... a non-equals sign followed by whitespace.
) # End $13. Non-prelinkified-proof prefix.
(\b # $14: Other non-delimited URL.
(?:ht|f)tps?:\/\/ # Required literal http, https, ftp or ftps prefix.
[a-z0-9\-._~!$\'()*+,;=:\/?#[\]@%]+ # All URI chars except "&" (normal*).
(?: # Either on a "&" or at the end of URI.
(?! # Allow a "&" char only if not start of an...
&(?:gt|\#0*62|\#x0*3e); # HTML ">" entity, or
| &(?:amp|apos|quot|\#0*3[49]|\#x0*2[27]); # a [&\'"] entity if
[.!&\',:?;]? # followed by optional punctuation then
(?:[^a-z0-9\-._~!$&\'()*+,;=:\/?#[\]@%]|$) # a non-URI char or EOS.
) & # If neg-assertion true, match "&" (special).
[a-z0-9\-._~!$\'()*+,;=:\/?#[\]@%]* # More non-& URI chars (normal*).
)* # Unroll-the-loop (special normal*)*.
[a-z0-9\-_~$()*+=\/#[\]@%] # Last char can\'t be [.!&\',;:?]
) # End $14. Other non-delimited URL.
/imx';
任何人都可以幫我或朝正確的方向嗎?非常感謝!
好吧,我想我明白你所有的解釋(針對TY!),沒有任何理由,只有我的第一個網址爲「一個」標籤之間,爲使?代碼的其餘部分:
$url_replace = '$1$4$7$10$13<a>$2$5$8$11$14</a>$3$6$9$12';
return preg_replace($url_pattern, $url_replace, $text);
如果
$text =
http://www.youtube.com/watch?v=Cy8duEIHEig http://www.youtube.com/watch?v=Cy8duEIHEig
只有第一個URL顯示爲URL。這件事與*有關嗎??
你的意思是最小的意思是什麼? – user111671
只要找到'?'後面的任何東西就會停下來 –
@JoaoRaposo你可以檢查答案更新嗎? – user111671