将csv文件的第一列解析为新文件 [英] Parsing the first column of a csv file to a new file

问题描述

操作系统：OSX
方法：从命令行，所以使用sed，cut，gawk，虽然最好不要安装模块。

Operating System: OSX Method: From the command line, so using sed, cut, gawk, although preferably no installing modules.

本质上，我试图获取csv文件的第一列并将其解析为一个新文件。

Essentially I am trying to take the first column of a csv file and parse it to a new file.

示例输入文件

EXAMPLEfoo,60,6
EXAMPLEbar,30,6
EXAMPLE1,60,3
EXAMPLE2,120,6
EXAMPLE3,60,6
EXAMPLE4,30,6

需要输出

EXAMPLEfoo 
EXAMPLEbar
EXAMPLE1
EXAMPLE2
EXAMPLE3
EXAMPLE4

所以我想要第一列。

这是我到目前为止所尝试的：

Here is what I have tried so far:

awk -F"," '{print $1}' in.csv > out.txt

awk -F"," '{for (i=2;i<=NF;i++)}' in.csv > out.txt

awk -F"," 'BEGIN { OFS="," }' '{print $1}' in.csv > out.txt

cat in.csv | cut -d \, -f 1 > out.txt

似乎没有效果，他们只是打印第一行或什么都没有，

None seem to work, either they just print the first line or nothing at all, so I would assume it's failing to read line by line.

推荐答案

您的最后一个选项对我来说是完美的：

Your last option works perfectly for me:

$ cat > in.csv
EXAMPLEfoo,60,6
EXAMPLEbar,30,6
EXAMPLE1,60,3
EXAMPLE2,120,6
EXAMPLE3,60,6
EXAMPLE4,30,6
[Ctrl+D]
$ cat in.csv | cut -d, -f1
EXAMPLEfoo
EXAMPLEbar
EXAMPLE1
EXAMPLE2
EXAMPLE3
EXAMPLE4

也许行结尾在这里咬你？如果文件具有DOS风格或甚至old-Mac风格的行结尾，这可能会导致奇怪的行为。尝试运行文件in.csv 并查看它出现了什么。

Maybe line endings are biting you here? If the file has DOS-style or even old-Mac-style line endings, this might cause strange behaviour. Try running file in.csv and see what it comes up with.

$ file in.unix.csv
in.unix.csv: ASCII text
$ file in.dos.csv
in.dos.csv: ASCII text, with CRLF line terminators

如果后者是您的情况，请使用 dos2unix

If the latter is your situation, use the dos2unix tool to convert the file.

编辑：在OS X上，它似乎 flip 是你想要的。

On OS X, it seems flip is what you want.

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