假设我有一个像这样的csv文件：
a,b1,12,
a,b1,42,
d,e1,12,
r,12,33,
我想使用grep只返回第三列= 12的行。所以它会返回：
a,b1,12,
d,e1,12,
但不是：
r,12,33,
正则表达式的任何想法都可以让我这样做吗？
答案 0 :(得分：27)
我会直接跳到awk来测试该值
awk -F, '$3 == 12' file.csv
这个以及任何基于正则表达式的解决方案都假定前两个字段的值不包含逗号
答案 1 :(得分：9)
grep "^[^,]\+,[^,]\+,12," file.csv
答案 2 :(得分：4)
以下是一个变体：
egrep "^([^,]+,){2}12," file.csv
优点是您可以简单地通过更改花括号中的数字来选择字段，而无需手动添加或减去模式的文字副本。
答案 3 :(得分：2)
如果你有csv文件，你有明确的分隔符，如逗号，使用分割字段/分隔符方法，而不是正则表达式。像awk一样打破字符串的工具，Perl / Python为您轻松完成工作（Perl / Python支持csv模块以进行更复杂的csv解析）
Perl，
$ perl -F/,/ -alne 'print if $F[2]==12;' file
a,b1,12,
d,e1,12,
$ awk -F"," '$3==12' file
a,b1,12,
d,e1,12,
或仅使用shell
while IFS="," read a b c d
do
case "$c" in
12) echo "$a,$b,$c,$d"
esac
done <"file"
答案 4 :(得分：1)
csvkit是一个很好的工具包，可用于此类操作，尤其是在较大规模的情况下。 installing csvkit之后，请按照以下说明隔离所需的行：
# Find rows that have the value 12 in the 3rd column
> csvgrep -c 3 -m 12 | csvlook
这应该打印出所需的行。 here可以找到csvkit的完整文档（以及写得很好的教程）。
答案 5 :(得分：0)
Linux工具实际上无法处理csv，因为引用字段可以包含根据rfc 1480的换行符。由于各种原因，大多数专用实用程序都是垃圾。
这是 Node.js v7.10 + 单文件可执行文件，它“正常工作”并生成转换后的json对象，每行一个。应该运行Linux macOS Windows
包含标题行的文件的用法：
cat infinite.csv | csv1480json --header
{"some header": "field value"}
没有标题行：
echo abc | csv1480json
{1: "abc"}
grep成为：
grep '3: "12"'
在你可以做的直立文本上
将其粘贴为可通过PATH访问的csv1480json并授予可执行权限：
#!/usr/bin/env node
/******/ (function(modules) { // webpackBootstrap
/******/ // The module cache
/******/ var installedModules = {};
/******/
/******/ // The require function
/******/ function __webpack_require__(moduleId) {
/******/
/******/ // Check if module is in cache
/******/ if(installedModules[moduleId]) {
/******/ return installedModules[moduleId].exports;
/******/ }
/******/ // Create a new module (and put it into the cache)
/******/ var module = installedModules[moduleId] = {
/******/ i: moduleId,
/******/ l: false,
/******/ exports: {}
/******/ };
/******/
/******/ // Execute the module function
/******/ modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
/******/
/******/ // Flag the module as loaded
/******/ module.l = true;
/******/
/******/ // Return the exports of the module
/******/ return module.exports;
/******/ }
/******/
/******/
/******/ // expose the modules object (__webpack_modules__)
/******/ __webpack_require__.m = modules;
/******/
/******/ // expose the module cache
/******/ __webpack_require__.c = installedModules;
/******/
/******/ // define getter function for harmony exports
/******/ __webpack_require__.d = function(exports, name, getter) {
/******/ if(!__webpack_require__.o(exports, name)) {
/******/ Object.defineProperty(exports, name, {
/******/ configurable: false,
/******/ enumerable: true,
/******/ get: getter
/******/ });
/******/ }
/******/ };
/******/
/******/ // getDefaultExport function for compatibility with non-harmony modules
/******/ __webpack_require__.n = function(module) {
/******/ var getter = module && module.__esModule ?
/******/ function getDefault() { return module['default']; } :
/******/ function getModuleExports() { return module; };
/******/ __webpack_require__.d(getter, 'a', getter);
/******/ return getter;
/******/ };
/******/
/******/ // Object.prototype.hasOwnProperty.call
/******/ __webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };
/******/
/******/ // __webpack_public_path__
/******/ __webpack_require__.p = "";
/******/
/******/ // Load entry module and return exports
/******/ return __webpack_require__(__webpack_require__.s = 0);
/******/ })
/************************************************************************/
/******/ ([
/* 0 */
/***/ (function(module, exports, __webpack_require__) {
"use strict";
var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
var _CsvJsonConverter = __webpack_require__(1);
var _CsvJsonConverter2 = _interopRequireDefault(_CsvJsonConverter);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
launch({ fn: _CsvJsonConverter2.default, getOptions, errorHandler }).catch(errorHandler);
function getOptions() {
const { argv } = process;
console.log('getOptions argv', argv);
const useHeader = argv[2] === '--header';
if (argv.length !== (useHeader ? 3 : 2)) throw new Error('usage: csv1480json [--header]');
return { readStream: process.stdin, writeStream: process.stdout, useHeader };
}
async function launch({ fn, getOptions, errorHandler }) {
process.on('uncaughtException', errorHandler).on('unhandledRejection', errorHandler);
new fn(_extends({}, getOptions(), { errorHandler }));
}
function errorHandler(e) {
console.error(e instanceof Error ? e /*TODO .message*/ : `errorHandler value: ${typeof e} ${e}`);
process.exit(1);
}
/***/ }),
/* 1 */
/***/ (function(module, exports, __webpack_require__) {
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
var _Pipeline = __webpack_require__(2);
var _Pipeline2 = _interopRequireDefault(_Pipeline);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
// getField result
const FIELD_EOF = 1; // end of file
const FIELD_NONE = 2; // data for complete field not seen yet
const FIELD_RECORD = 3; // got a complete record
const separators = Array.from(',\r\n');
class CsvJsonConverter extends _Pipeline2.default {
constructor(o) {
super(o || false);
this.addData = string => this.csv += string;
this.isField = s => typeof s === 'string';
const { useHeader } = o || false;
this.useHeader = !!useHeader;
this.csv = '';
this.recordNo = 1;
console.log(this.useHeader, Object.keys(o || false));
}
getOutput(isEnd) {
if (isEnd) this.isEnd = true;
if (this.useHeader && !this.headers) if (!this.getHeader()) return;
let output = '';
for (let record; record = this.getRecord(); output += record + '\n');
return output || undefined;
}
getRecord() {
const fields = this.getFieldList();
if (fields) {
// got a record
const count = fields.length;
const { fieldCount, recordNo, useHeader, headers } = this;
if (!fieldCount) this.fieldCount = count;else if (count !== fieldCount) throw new Error(`Record ${recordNo} bad field count: ${count} expected ${fieldCount}`);
this.recordNo++;
return `{${fields.map((v, index) => `${useHeader ? headers[index] : index + 1}: ${JSON.stringify(v)}`).join(', ')}}`;
} else return false;
}
getHeader() {
const list = this.getFieldList();
if (list) {
this.headers = list.map(v => JSON.stringify(v));
this.fieldCount = list.length;
}
}
getFieldList() {
// array of string or false
let fields = this.fields || (this.fields = []);
let field;
while (this.isField(field = this.getField())) fields.push(field);
console.log('getFieldList end:', field, fields);
if (field === FIELD_RECORD) {
this.fields = null;
return fields;
} else return false; // need to wait for more data or end of records
}
getField() {
// string or FIELD_*
const { isEnd, recordNo } = this;
const fields = this.fields.length;
let { csv } = this;
let csvCh = csv[0];
if (csvCh === '\r' || csvCh === '\n') {
// skip the end of line terminating a previous record
if (csv.length < 2 && !isEnd) return FIELD_NONE; // must have two characters to find \r\n
const chs = csv.substring(0, 2) === '\r\n' ? 2 : 1;
this.csv = csv = csv.substring(chs);
return FIELD_RECORD; // we have a complete record
}
if (!csv && isEnd) return fields ? FIELD_RECORD : FIELD_EOF;
const m = `Record ${recordNo} field ${fields + 1}`;
if (fields) if (csvCh === ',') csvCh = (this.csv = csv = csv.substring(1))[0];else throw new Error(`${m} missing field-separating comma`); // TODO insert location
if (csvCh === '"') {
// double-quoted field
let quoteSearchIndex = this.quoteSearchIndex || 1; // where to start looking
let index;
for (;;) {
let index = csv.indexOf('"', quoteSearchIndex);
if (!~index) // no end-quote yet
if (!isEnd) {
this.quoteSearchIndex = quoteSearchIndex;
return FIELD_NONE; // no matching quote in data thus far
} else throw new Error(`${m} unmatched double quote`);
if (index - quoteSearchIndex < 2 || csv[index - 1] !== '\\') {
// found unescaped ending double quote
this.quoteSearchIndex = 0;
this.csv = csv.substring(index + 1);
return csv.substring(1, index);
}
quoteSearchIndex = index + 1; // skip escaped double quote
}
}
// it is an unquoted field
const index = separators.map(ch => csv.indexOf(ch)).reduce((r, index) => !~index ? r : !~r ? index : Math.min(r, index));
if (!~index) // none of the separators appeared
if (isEnd) {
this.csv = '';
return csv; // field is rest of line
} else return FIELD_NONE; // need more data
this.csv = csv.substring(index);
return csv.substring(0, index);
}
}
exports.default = CsvJsonConverter;
/***/ }),
/* 2 */
/***/ (function(module, exports, __webpack_require__) {
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
var _stream = __webpack_require__(3);
class PipeLine extends _stream.Transform {
constructor({ readStream, writeStream, errorHandler }) {
super({ decodeStrings: false, encoding: 'utf8' });
this._flush = callback => callback(null, this.getOutput(true));
const eh = typeof errorHandler;
if (eh !== 'function') throw new Error(`PipeLine: errorHandler not function: ${eh}`);
readStream.on('error', errorHandler).setEncoding('utf8').pipe(this.on('error', errorHandler)).pipe(writeStream.on('error', errorHandler));
}
_transform(chunk, encoding, callback) {
// callback(err, chunk)
if (chunk.length) this.addData(chunk);
callback(null, this.getOutput());
}
}
exports.default = PipeLine; /*
© 2017-present Harald Rudell <harald.rudell@gmail.com> (http://www.haraldrudell.com)
This source code is licensed under the ISC-style license found in the LICENSE file in the root directory of this source tree.
*/
/***/ }),
/* 3 */
/***/ (function(module, exports) {
module.exports = require("stream");
/***/ })
/******/ ]);
//# sourceMappingURL=csv1480json.js.map
答案 6 :(得分：0)
我不知道效率（很想知道），这行得通
cat path/to/file.csv | grep <some-text>