Created
April 22, 2016 09:27
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宣告某token xyz++ 在讀的時候只會讀到xyz就會印出找到該token | |
解決方式 | |
1.使用 xyz”++” or “xyz++” | |
2.使用 xyz\+\+ | |
[abc] 表示只要符合abc其中之一 | |
[a-z0-9<>_] 表示a~z, 0~9 , <, >, _ 其中之一符合就可 | |
但因為有a-z這種表示方式,所以導致如果要當 “-“也列入考量 | |
“-“必須擺在最一開始或最後, Ex: [-+0-9] | |
[^abc] 表示符合 非a, b, c | |
ab?c 表示 ?前的character可有可無 —> ac, abc都可 | |
a* 表示接受所有 空, a, aa, aaa, aaaa, …….. | |
a+ 表示接受所有 a, aa, aaa, aaaa, …….(沒有空) | |
ab | cd 表示接受 ab, cd |
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