character set
内的caret
符( ^
)来创建[^thingsThatWillNotBeMatched]
形式的negated character set
。在character set
, caret
用于在字符串的开头搜索模式。 让firstString =“Ricky是第一个,可以找到。”;
让firstRegex = / ^ Ricky /;
firstRegex.test(firstString);
//返回true
让notFirst =“你现在找不到Ricky了。”;
firstRegex.test(notFirst);
//返回false
caret
只能在字符串rickyAndCal
的开头找到"Cal"
。 "Cal"
。
testString: 'assert(calRegex.source == "^Cal", "Your regex should search for "Cal"
with a capital letter.");'
- text: 你的正则表达式不应该使用任何标志。
testString: 'assert(calRegex.flags == "", "Your regex should not use any flags.");'
- text: 你的正则表达式应该匹配字符串开头的"Cal"
。
testString: 'assert(calRegex.test("Cal and Ricky both like racing."), "Your regex should match "Cal"
at the beginning of the string.");'
- text: 您的正则表达式不应与字符串中间的"Cal"
匹配。
testString: 'assert(!calRegex.test("Ricky and Cal both like racing."), "Your regex should not match "Cal"
in the middle of a string.");'
```