打印 CSV 的前 N ​​行，其中引用的字段可以包含换行符

Posted 2023-03-15

【中文标题】打印 CSV 的前 N ​​行，其中引用的字段可以包含换行符

【英文标题】：Print the first N lines of a CSV where quoted fields can contain newlines

【发布时间】：2021-09-29 18:03:16

【问题描述】：

CSV 文件可以包含带有换行符的数据。它可以与任何列一起使用。此外，某些行可以包含没有任何新行的数据，因此它应该在所有情况下都可以使用

示例输入

   ID,username,mobile,city,Message,Address,city
'11111111',TestUSer,1234567890,test,"Hi how are you? Well: we will connnect

Thanks for your time!
With Joy.
Test",Address test,City test
11111116,TestUser,1234567891,test,hello msg,Address test1,City test1
'111111167',TestUSer,1234567890,test,"Hi how are you one? Well: we will connnect

Thanks for your time!
With Joy.
Test",Address test,City test
11111112,TestUser,1234567891,test1,hello msg1,Address test2,City test2
11111113,TestUser,1234567891,test1,hello msg1,Address test2,City test2
11111114,TestUser,1234567891,test1,hello msg1,Address test2,City test2

我正在使用以下命令读取 csv 的前 5 条记录

awk -v RS='("[^"]*")?\r?\n' 'NFORS = gensub(/\r?\n(.)/, "\\\\n\\1", "g", RT);  ++n; print n==5exit' file.csv

实际输出：

ID,username,mobile,city,Message,Address,city
'11111111',TestUSer,1234567890,test,"Hi how are you? Well: we will connnect\nThanks for your time!\nWith Joy.\Test",Address test,City test
11111116,TestUser,1234567891,test,hello msg,Address test1,City test1
'111111167',TestUSer,1234567890,test,"Hi how are you one? Well: we will connnect\nThanks for your time!\nWith Joy.\nTest",Address test,City test
11111112,TestUser,1234567891,test1,hello msg1,Address test2,City test2
11111113,TestUser,1234567891,test1,hello msg1,Address test2,City test2
11111114,TestUser,1234567891,test1,hello msg1,Address test2,City test2

想要的输出：

ID,username,mobile,city,Message,Address,city
'11111111',TestUSer,1234567890,test,"Hi how are you? Well: we will connnect\nThanks for your time!\nWith Joy.\Test",Address test,City test
11111116,TestUser,1234567891,test,hello msg,Address test1,City test1
'111111167',TestUSer,1234567890,test,"Hi how are you one? Well: we will connnect\nThanks for your time!\nWith Joy.\nTest",Address test,City test
11111112,TestUser,1234567891,test1,hello msg1,Address test2,City test2

【参考方案1】：

仅使用您展示的示例，您能否尝试遵循awk 代码。使用 GNU awk 编写和测试。使用RS记录分隔符，然后全局替换以使RT中的新行无效，然后相应地打印行。

awk -v RS='"[^"]*"' 'gsub(/\n/,"\\n",RT);ORS=RT 1' Input_file

要获取前 10 条记录，请尝试以下操作：

awk -v RS='"[^"]*"' 'gsub(/\n/,"\\n",RT);ORS=RT 1' Input_file | head -10

【参考方案2】：

警告：提前自我宣传！

我编写了一个类似于awk 的实用程序，名为tawk，它使用 tcl 作为其脚本语言，并且具有读取 CSV 数据的模式，而无需使用正则表达式来处理嵌入了换行符和引号的记录（这功能实际上是我的主要灵感来源）。

使用它：

$ tawk -csv 'line $NR <= 5  puts [regsub -all \n+ $F(0) "\\n"]; if $NR == 5 exit ' input.csv
ID,username,mobile,city,Message,Address,city
'11111111',TestUSer,1234567890,test,"Hi how are you? Well: we will connnect\nThanks for your time!\nWith Joy.\nTest",Address test,City test
11111116,TestUser,1234567891,test,hello msg,Address test1,City test1
'111111167',TestUSer,1234567890,test,"Hi how are you one? Well: we will connnect\nThanks for your time!\nWith Joy.\nTest",Address test,City test
11111112,TestUser,1234567891,test1,hello msg1,Address test2,City test2