我有多行字符串现在我想打印那些包含特定子字符串的行答案

【问题标题】：I have multiple lines of string now i want to print those lines who contains particular substring我有多行字符串现在我想打印那些包含特定子字符串的行
【发布时间】：2019-02-25 18:33:58
【问题描述】：

Here i want to print line which contains following strings: 
Object.< anonymous >

这是多行：现在找到那些包含子字符串 Object 的行。

Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'yourusername'@'localhost' (using password: YES)
at Socket.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/node_modules/mysql/lib/Connection.js:91:28)
at Object.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/conn.js:10:5)
at Module._compile (internal/modules/cjs/loader.js:686:14)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)

输出应该是：在 Object. (/home/abc/Desktop/AJ/CustomLogger/conn.js:10:5)

【问题讨论】：

标签： javascript arrays node.js string npm

【解决方案1】：

您可以拆分字符串并首先获取所有行，然后检查Object.< anonymous >（有或没有regex) 过滤掉它们。

let str = `Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'yourusername'@'localhost' (using password: YES)
at Socket.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/node_modules/mysql/lib/Connection.js:91:28)
at Object.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/conn.js:10:5)
at Module._compile (internal/modules/cjs/loader.js:686:14)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)`,

res = str.split("\n").filter(line=>line.indexOf("Object.< anonymous >")>-1);

console.log(res);

或者，您可以匹配带有多行标志的regex (m)

let str = `Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'yourusername'@'localhost' (using password: YES)
at Socket.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/node_modules/mysql/lib/Connection.js:91:28)
at Object.< anonymous > (/home/abc/Desktop/AJ/CustomLogger/conn.js:10:5)
at Module._compile (internal/modules/cjs/loader.js:686:14)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)`,

res = str.match(/^(.*Object\.< anonymous >.*)$/mg);

console.log(res);

【讨论】：