了解AWK和CSV文件 [英] Understanding AWK and CSV files

问题描述

如何编写AWK程序来分析CSV文件中的字段列表，计算指定字段中每个不同字符串的数量，并打印出找到的每个字符串的数量?我只用C和Java编写过代码，所以我对AWK的语法完全感到困惑.我了解最简单的概念，但是AWK的结构却大不相同.随时感谢，谢谢！

How can I write an AWK program that analyses a list of fields in CSV files, count the number of each different string in the specified field, and print out the count of each string that is found? I have only coded in C and Java, so I am completely confused on the syntax of AWK. I understand the simplest of concepts, however, AWK is structured much differently. Any time is appreciated, thank you!

BEGIN {
    FS = ""
}
{
    for(i = 1; i <= NF; i++) 
        freq[$i]++
    PROCINFO ["sorted_in"] = "@val_num_desc" #this got the desired result
}
END {
    for {this in freq) 
        printf "%s\t%d\n", this, freq[this]
}

在包含以下内容的CSV文件中

On a CSV file containing:

Field1, Field2, Field3, Field4
A, B, C, D
A, E, F, G
Z, E, C, D
Z, W, C, Q

我能够获得结果:

A     2
B     1
C     3
Q     1
D     1
E     2
F     1
,     12
G     1
W     1
Field1,Field2,Field3,Field4     1
Z     2

这是理想的结果:

A       10
C       7
D       2
E       2
Z       2
B       1
Q       1
Field1  1
Field2  1
F       1
Field3  1
G       1
Field4  1
W       1

我的代码有一个修改，并带有注释.

There is an edit to my code which is commented.

推荐答案

修复了您的代码:

$ awk '
BEGIN {                                     # you need BEGIN block for FS
    FS = ", *"                              # your data had ", " and "," seps
}                                           # ... based on your sample output
{
    for(i = 1; i <= NF; i++)
        freq[$i]++
}
END {
    for(this in freq)                       # fixed a parenthesis
        printf "%s\t%d\n", this, freq[this]
}' file

输出(使用GNU awk.其他awk以不同的顺序显示输出):

Output (using GNU awk. Other awks displayed output in different order):

A       2
B       1
C       3
Q       1
D       2
Field1  1
E       2
Field2  1
F       1
Field3  1
G       1
Field4  1
W       1
Z       2

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