我试图从一个更大的字符串中提取一个字符串,它得到了a:和a之间的所有东西;
当前的
Str = 'MyLongString:StringIWant;'
期望输出值
newStr = 'StringIWant'
我试图从一个更大的字符串中提取一个字符串,它得到了a:和a之间的所有东西;
当前的
Str = 'MyLongString:StringIWant;'
期望输出值
newStr = 'StringIWant'
当前回答
这是我刚做的东西。
注意,如果在启动后没有找到end,函数将返回启动后的所有内容。它还期望只有一次出现的开始和结束,如果有多次,它将只考虑第一次。
许可:公共领域
/**
* Extracts a string from `source` that is placed between `start` and `end`. The function
* considers only one instance of start and before, or the first instance and does not support
* multiple occurences otherwise. If end string is not found, it will return everything after
* `start` to the end of the string.
*/
export function stringBetween(source, start, end) {
if (source.indexOf(start) === -1) {
return null;
}
const sourceSplitByStartString = source.split(start);
// Note: If start string is the very first occurence in source string, the result will be an
// array where the first item is an empty string and the next item is of interest.
if (
sourceSplitByStartString.length === 1
|| sourceSplitByStartString[1] === ''
) {
// It means that start is either the entire string or is at the very end of the string, so there
// is not anything between
return '';
}
const afterStart = sourceSplitByStartString[1];
// If the after separator is not found, return everything after the start separator to the end
// of the string
if (afterStart.indexOf(end) === -1) {
return afterStart;
}
const afterStartSplitByEnd = afterStart.split(end);
if (afterStartSplitByEnd[0] === '') {
return '';
}
return afterStartSplitByEnd[0];
}
测试:
import { stringBetween } from './string';
describe('string utlities', () => {
describe('stringBetween', () => {
it('Extracts a substring between 2 other substrings', () => {
const sample1 = stringBetween('Black cat climbed the tree fast.', 'cat ', ' the tree');
expect(sample1).toBe('climbed');
const sample2 = stringBetween('Black cat climbed the tree fast.', 'Black ', ' fast.');
expect(sample2).toBe('cat climbed the tree');
});
it('extracts everything after start if end is not found', () => {
const sample2 = stringBetween('Black cat climbed the tree fast.', 'Black ', 'not-there');
expect(sample2).toBe('cat climbed the tree fast.');
});
it('returns empty string if start string occurs at the end', () => {
const sample = stringBetween('Black cat climbed the tree fast.', 'fast.', 'climbed');
expect(sample).toBe('');
});
it('returns empty string if start string is the entire string', () => {
const sample = stringBetween('Black cat', 'Black cat', 'climbed');
expect(sample).toBe('');
});
it('returns empty string if there is not anything between start and end', () => {
const sample = stringBetween('Black cat climbed the tree fast.', 'climbed ', 'the tree');
expect(sample).toBe('');
});
it('returns null if start string does not exist in the source string', () => {
const sample = stringBetween('Black cat climbed the tree fast.', 'not-there ', 'the tree');
expect(sample).toBe(null);
});
});
});
其他回答
var s = 'MyLongString:StringIWant;';
/:([^;]+);/.exec(s)[1]; // StringIWant
function substringBetween(s, a, b) {
var p = s.indexOf(a) + a.length;
return s.substring(p, s.indexOf(b, p));
}
// substringBetween('MyLongString:StringIWant;', ':', ';') -> StringIWant
// substringBetween('MyLongString:StringIWant;;', ':', ';') -> StringIWant
// substringBetween('MyLongString:StringIWant;:StringIDontWant;', ':', ';') -> StringIWant
您可以使用这个函数-
function getStringInBetween(string, start , end) {
// start and end will be excluded
var indexOfStart = string.indexOf(start)
indexOfStart = indexOfStart + start.length;
var newString = string.slice(indexOfStart)
var indexOfEnd = newString.indexOf(end)
return newString.slice(0, indexOfEnd)
}
对于前-
let string = "<div class = 'mice'> I know how to code </div>"
let start = "<div class = 'mice'> "
let end = " </div>"
//then, getStringInBetween(string, start, end) returns "I know how to code"
使用分割()
var s = 'MyLongString:StringIWant;';
var arrStr = s.split(/[:;]/);
alert(arrStr);
arrStr将包含所有由:或; 通过for循环访问每个字符串
for(var i=0; i<arrStr.length; i++)
alert(arrStr[i]);
下面的函数获取第一个匹配项
function getStringBetween(x: string, start: string, end: string) {
const regex = new RegExp(`${start}(.*?)${end}`)
if (regex.test(x)) {
return regex.exec(x)![1]
} else return undefined
}
有测试
test("getStringBetween", () => {
const result = getStringBetween("<em> Jai Ram</em>", "<em>", "</em>")
expect(result).toEqual(" Jai Ram")
const result1 = getStringBetween(
"hare Jai Ram hare hare hare",
"hare",
"hare"
)
expect(result1).toEqual(" Jai Ram ")
})