原创 正則表達式學習指南(九)----Alternation
I already explained how you can use character classes to match a single character out of several possible characters. A
2020-06-23 10:05:52
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原创 正則表達式學習指南(十六)----Possessive Quantifiers
Possessive Quantifiers When discussing the repetition operators or quantifiers, I explained the difference between gree
2020-06-23 10:05:52
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原创 正則表達式學習指南(十)----Making a Token Optional
Optional Items The question mark makes the preceding token in the regular expression optional. E.g.: colou?r matches bo
2020-06-23 10:05:40
原创 正則表達式學習指南(二十四)----Adding Comments
Adding Comments to Regular Expressions If you have worked through the entire tutorial, I guess you will agree that regu
2020-06-23 10:05:40
原创 正則表達式學習指南(十九)----Testing The Same Part of a String for More Than One
Testing The Same Part of a String for More Than One Requirement Lookaround, which I introduced in detail in the previou
2020-06-23 10:05:40
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原创 一個關於JOIN的SQL語句
問題描述:抓取程序的結果精度不夠,導致入庫的數據有的正確,有的錯誤,需要找出錯誤的數據. 抓取下來的數據有三個值,最高價,最低價和平均值.其中最高價和最低價由網頁提供,平均值是自己算出來的,但是平均值被強制轉換爲了int類型,所以導致了精
2020-06-23 10:05:40
原创 正則表達式學習指南(十七)----Atomic Grouping
Atomic Grouping An atomic group is a group that, when the regex engine exits from it, automatically throws away all bac
2020-02-25 11:30:41
原创 正則表達式語言元素
正則表達式語言元素(轉自MSDN) .NET Framework 4 其他版本 正則表達式是正則表達式引擎嘗試匹配輸入文本的一種模式。 模式由一個或多個字符文本、運算符或構造組成。 有關簡單介紹
2020-02-25 11:30:31
原创 正則表達式學習指南(十四)----Unicode
Unicode Regular Expressions Unicode is a character set that aims to define all characters and glyphs from all human lan
2020-02-25 11:30:31
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原创 正則表達式學習指南(二十三)----POSIX Bracket Expressions
POSIX Bracket Expressions POSIX bracket expressions are a special kind of character classes. POSIX bracket expressions
2020-02-25 11:30:31
原创 正則表達式學習指南(二十五)----Free-Spacing Regexes
Free-Spacing Regular Expressions The JGsoft engine, .NET, Java, Perl, PCRE, Python, Ruby and XPath support a variant
2020-02-25 11:30:31
原创 正則表達式學習指南(十一)----Quantifiers(Repetition)
Repetition with Star and Plus I already introduced one repetition operator or quantifier: the question mark. It tells t
2020-02-25 11:30:31
原创 正則表達式學習指南(十五)----Mode Modifiers
Regex Matching Modes Most regular expression engines discussed in this tutorial support the following four matching mod
2020-02-25 11:30:31
原创 正則表達式學習指南(二十一)----If-Then-Else Conditionals
If-Then-Else Conditionals in Regular Expressions A special construct (?ifthen|else) allows you to create conditional re
2020-02-25 11:30:31
原创 正則表達式學習指南(二十)----Continuing from The Previous Match
Continuing at The End of The Previous Match The anchor \G matches at the position where the previous match ended. Durin
2020-02-25 11:30:31