不使用正则表达式 Javascript 删除两个字符之间的字符串

Question

我试图从我通过输入文件上传的文本文件中删除一个句子。 我需要删除'/ '和' /'之间的所有句子，所以基本上是注释行。 还有所有单行注释，例如“//”，但我已经处理好了。 为此，我不允许使用任何正则表达式或替换功能。 有没有人可以帮助我？ 谢谢

class Inpute extends Component{
  constructor(props){
    super(props);
    this.state = {
      fileName: '',
      fileContent: ''
    };
  }

  handleFile = e =>{
    const file = e.target.files[0];
    const reader = new FileReader();
    reader.readAsText(file);
    reader.onload = () => {
      this.setState({fileName: file.name, fileContent: reader.result});
      if(reader.result.includes('//')){
        var newText = reader.result
        newText = newText
                .split('\n')
                .filter(x => !x.includes('\/\/'))
                .join('\n')

        this.setState({fileName: file.name, fileContent: newText})
      }
    }
    reader.onerror = () =>{
      console.log('File Error : ', reader.error)
    }
  }

Answer 1

通过/分割字符串。 您需要删除的部分都在奇数索引中，因此将它们过滤掉并将此数组连接回字符串。

 const string = 'asdasada a/kkkkkkkk/a sdad asda s/xxxxx/s dasd'; const arr = string.split('/').filter((_, index) => index%2 === 0); console.log(arr.join(''));

更新

我已更改示例以仅过滤评论

 const line = 'asdasada a/*kkkkkkkk*/a sdad asda s/*xxxxxs dasd x asda sd\\n' + 'asdas */das a// asdasda\\n' + 'x/*bbbbb*/c ad'; let prevPart = null; let haveDoubleSlashes = false; const cleaned = line.split('/').map(part => { // single line comments if (haveDoubleSlashes || part === '') { haveDoubleSlashes = true; if (part.includes('\\n')) { part = '\\n' + part.split('\\n')[1]; haveDoubleSlashes = false; } else { part = null; } return part; } /* multiline comments */ if (part.startsWith('*') && part.endsWith('*')) { prevPart = null; return null; } if (prevPart !== null) { part = '/' + part; } prevPart = part; return part; }).filter(part => part !== null).join(''); console.log(cleaned);

Answer 2

如果您只关心该行是否包含两个实线字符 ( / )，只需对其进行过滤：

 const sample = `blah blah // blah blah\\nblah blah /blah blah/ blah\\nblah blah blah`; const lines = sample.split('\\n'); const good = lines.filter(x => // [...x] makes the line an array of characters // reduce runs for each character, aggregating the result. // agg is the aggregation, cur is the current character // Here it's just counting the number of /s and returning false if there are // fewer than two [...x].reduce((agg, cur) => agg = cur === '/' ? agg + 1 : agg, 0) < 2 ); console.log(good.join('\\n'));

Answer 3

 function stripMultilineComments(str) { let posOpen; let posClose; while ((posOpen = str.indexOf('/*')) !== -1) { posClose = Math.max( 0, str.indexOf('*/', (posOpen + 2)) ) || (str.length - 2); str = [ str.substring(0, posOpen), str.substring(posClose + 2), ].join(''); } return str; } function stripSingleLineComment(str) { let idx; if ( (str.trim() !== '') && ((idx = str.indexOf('//')) !== -1) ) { str = str.substring(0, idx); } return str; } function stripComments(value) { return stripMultilineComments( String(value) ) .split('\\n') .map(stripSingleLineComment) .join('\\n'); } const sampleData = ` Lorem ipsum dolor sit amet/*, consectetur adipiscing elit, sed do eiusmod tempor incididunt*/ ut labore et dolore magna aliqua. // Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris/*nisi ut aliquip ex ea commodo consequat*/. Duis aute irure dolor in reprehenderit// in voluptate velit esse cillum dolore eu fugiat nulla pariatur.// Excepteur sint occaecat /*cupidatat non proident, */sunt in culpa qui officia deserunt mollit anim id est laborum. `; console.log( stripComments(sampleData) ); console.log( stripComments(sampleData) === ` Lorem ipsum dolor sit amet ut labore et dolore magna aliqua. quis nostrud exercitation ullamco laboris. Duis aute irure dolor in reprehenderit eu fugiat nulla pariatur. sunt in culpa qui officia deserunt mollit anim id est laborum. `);

 .as-console-wrapper { min-height: 100%!important; top: 0; }