Question

我试图提取字符串的一部分并在javascript中使用正则表达式替换它。例如：

var string = "application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1"

我需要替换

packet.vlan == 10

带

packet.vlan == VLAN-10

我试过以下

var regexp = /(\=.+)/g;
string.replace(regexp, ("==" + "VLAN-10");

选择必须在下一个OR/AND停止。如果例如上述选择必须在字符串ip开始之前停止。

Answer 1

你的正则表达式意味着“找到任何'='符号后跟一个或多个字符。”

您可以查看https://regex101.com/，它提供了调试正则表达式的可视方式。

尝试string.replace(/(packet\.vlan == )(\d+)/, "$1VLAN-$2");

注意：“string”是变量的一个非常糟糕的名称。

Answer 2

您可以使用正则表达式替换字符串，g中的RegExp标识符用作global匹配（查找所有匹配项，而不是在第一次匹配后停止）。

var string = "application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1"

var temp = new RegExp("packet.vlan == 10", "g");
console.log(string.replace(temp, "packet.vlan == VLAN-10"));

要将packet.vlan == 10的第一次出现替换为VLAN-10，您只需使用.replace()。

var string = "application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1 AND packet.vlan = 11.1.1.1.11"
console.log(string.replace("packet.vlan == 10", "packet.vlan == VLAN-10"));

Answer 3

解决方案是重写你的正则表达式：

＆＃13;

var regexp = /(==\s)(.+\b)/g;  //all chars from ==whitespace until next word boundery
    var s = "packet.VLAN == 10".replace(regexp, "== VLAN-$2"); //$2 to refer to the capturing group
    console.log(s);

＆＃13;

然而，对于这些复杂的sql字符串，我会使用其他JavaScript来确保更多控制。看看：

＆＃13;

var SQLString = "application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1";


var edit = SQLString.split(/AND|OR/i); //split on and or
var andOrs = SQLString.match(/AND|OR/ig); //create an array with and an or.
edit.forEach(function(value, index, arr){
    //loop the array
    var prop = value.substr(0, value.trim().search(/\s/)+1).trim(); //trim the whitespaces.
    switch(prop){
       case "packet.vlan" :
           arr[index] = "packet.vlan == VLAN-" +value.split("==")[1].trim();
       break;
    }
    
    //add the original and or to it.
    andOrs[index] ? arr[index] = arr[index].trim() + " " + andOrs[index].trim() : null;
});

SQLString = edit.join(" "); //join the array parts with a whitespace.
console.log(SQLString);

＆＃13;

最后一点。我很好奇为什么需要JavaScript来重写SQL字符串？

Answer 4

试试这个，

const regex = /packet.vlan == (\d+)/g;
const str = `application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1`;
const subst = `packet.vlan == VLAN-$1`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);

console.log('Substitution result: ', result);

请参阅正则表达式：https://regex101.com/r/93AfJr/1

OR

const str = `application == xyz AND location == abc AND packet.vlan == 10 OR ip == 1.1.1.1`;
var newstr = str.replace(/packet.vlan == 10/i, 'packet.vlan == VLAN-10');
console.log(newstr);

Answer 5

因为我必须找到packet.xxx的字符串并用值替换它。我不得不循环查找包含数据包的字符串。并使用正则表达式替换它。

注意：在packet.xxx中，xxx可以是任何动态值。

使用带有javascript的正则表达式仅提取字符串的一部分

5 个答案: