bash 将 csv 文件的第一列解析为新文件
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Parsing the first column of a csv file to a new file
提问by S1syphus
Operating System: OSX Method: From the command line, so using sed, cut, gawk, although preferably no installing modules.
操作系统：OSX 方法：从命令行，因此使用 sed、cut、gawk，但最好不要安装模块。
Essentially I am trying to take the first column of a csv file and parse it to a new file.
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。
Example input 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
Desire output
欲望输出
EXAMPLEfoo
EXAMPLEbar
EXAMPLE1
EXAMPLE2
EXAMPLE3
EXAMPLE4
So I want the first column.
所以我想要第一列。
Here is what I have tried so far:
这是我迄今为止尝试过的：
awk -F"," '{print }' in.csv > out.txt
awk -F"," '{for (i=2;i<=NF;i++)}' in.csv > out.txt
awk -F"," 'BEGIN { OFS="," }' '{print }' in.csv > out.txt
cat in.csv | cut -d \, -f 1 > out.txt
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.
似乎没有任何工作，他们要么只打印第一行，要么根本不打印，所以我认为它无法逐行读取。
回答by Thomas
Your last option works perfectly for me:
您的最后一个选项非常适合我：
$ cat > in.csv # Then pasted the example input followed by Ctrl+D:
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
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.csvand see what it comes up with.
也许行尾在这里咬你？如果文件具有 DOS 风格甚至旧 Mac 风格的行尾，这可能会导致奇怪的行为。尝试运行file in.csv，看看它会出现什么。
$ file in.unix.csv
in.unix.csv: ASCII text
$ file in.dos.csv
in.dos.csv: ASCII text, with CRLF line terminators
If the latter is your situation, use the dos2unixtool to convert the file.
如果您的情况是后者，请使用该dos2unix工具转换文件。
Edit: On OS X, it seems flipis what you want.
编辑：在 OS X 上，它似乎flip是你想要的。
回答by Personman
I copy-pasted your sample input, saved it as in.csv, and then ran your first line,
我复制粘贴了您的示例输入，将其另存为 in.csv，然后运行您的第一行，
awk -F"," '{print }' in.csv > out.txt
and it worked perfectly, like so:
它工作得很好，就像这样：
$ emacs in.csv
$ cat in.csv
EXAMPLEfoo,60,6
EXAMPLEbar,30,6
EXAMPLE1,60,3
EXAMPLE2,120,6
EXAMPLE3,60,6
EXAMPLE4,30,6
$ awk -F"," '{print }' in.csv > out.txt
$ cat out.txt
EXAMPLEfoo
EXAMPLEbar
EXAMPLE1
EXAMPLE2
EXAMPLE3
This is in Terminal.app on OS X 10.5
这是在 OS X 10.5 上的 Terminal.app 中
回答by Michal ?iha?
For me, cut produces expected result:
对我来说， cut 产生预期的结果：
cut -d, -f1 < in.csv > out.txt
回答by Chris Koknat
If Perl is an option:
如果 Perl 是一个选项：
perl -F, -lane 'print $F[0]' in.csv > out.txt
perl -F, -lane 'print $F[0]' in.csv > out.txt
These command-line options are used:
使用这些命令行选项：
-nloop around every line of the input file-lremoves newlines before processing, and adds them back in afterwards-aautosplit mode – split input lines into the@Farray. Defaults to splitting on whitespace.-eexecute the perl code-Fautosplit modifier, in this case splits on,
-n循环输入文件的每一行-l在处理之前删除换行符，然后将它们添加回-a自动拆分模式 – 将输入行拆分到@F数组中。默认为在空白处拆分。-e执行perl代码-F自动拆分修饰符，在这种情况下拆分,
@Fis the array of words in each line, indexed starting with $F[0]
@F是每行中的单词数组，索引以 $F[0]
