javascript - read tab delimited file, line by line

2020-07-06 02:01发布

站内问答 / JavaScript
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I'm able to read a file line by line but I do not know how to split each lines using the tab delimited. here my code. Need some help on this issue

    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title>Sum of a Column in JavaScript</title>
    </head>

    <input type="file" name="file" id="file">

    <script type="text/javascript">

    document.getElementById('file').onchange = function(){

    var file = this.files[0];

    var reader = new FileReader();
    reader.onload = function(progressEvent){
    // Entire file
    console.log(this.result);

    // By lines
    var lines = this.result.split('\n');
    for(var line = 0; line < lines.length; line++){
        // By tabs
        var tabs = lines[line].split('\\t');
        for(var tab = 0; tab < tabs.length; tab++){    
                alert(tabs[tab]);
        }   
    }
  };
  reader.readAsText(file);
};

</script>

标签： javascript
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2条回答
一夜七次
2楼-- · 2020-07-06 02:45

I found this useful, and replaced the for ... loops with the js .map() function. Also, I load data into arrays:

    // By lines
    var arr1 = [];
    var arr2 = [];
    var arr3 = [];
    var arr4 = [];
    var arr5 = []; // assuming 5 tabs
    var lines = this.result.split('\n');
    lines.map(function(item){
      var tabs = item.split('\t');
      console.log("0",tabs[0], "1",tabs[1], "2",tabs[2],"3", tabs[3],"4", tabs[4], "5", tabs[5], "6", tabs[6]);
      arr1.push(tabs[0]);
      arr2.push(tabs[1]);
      arr3.push(tabs[2]);
      arr4.push(tabs[3]);
      arr5.push(tabs[4]);
    });
    // test two of the arrays after reading:
    for (var i = 0; i < mdarr.length; i++) {
      console.log(arr1[i], arr2[i]);
    };
  }
  reader.readAsText(file);
};
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爷、活的狠高调
3楼-- · 2020-07-06 02:49

Here is how I converted a tab delimited file to a tree format in Node

var inputFile='Tree.tab'
fs = require('fs');

tree = {} 
fs.readFile(inputFile, 'ascii', function(err, data) {
    if(err) {
        console.log(err);
    }
    lines = data.split('\r\n');
    lines.map(function(line){
        levels = line.split("\t");
        if(typeof tree[levels[0]] === "undefined") {
           tree[levels[0]] = {}
        }
        node = tree[levels[0]]
        for ( var i = 1; i < levels.length; i++) {
            if(typeof node[levels[i]] === "undefined") {
                node[levels[i]] = {}
            }
        }

    });
    console.log(tree);
});
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