AWK: How to merge CSV files and eliminate rows that contain certain values? - csv

Question

I have hundreds of CSV files. Each CSV file is similar to this:
| KEYWORD | NUMBER OF COMPS | AVGE M E (K) | GS/M | EST. A SE/M | C CORE |
|---------|-----------------|--------------|------|-------------|--------|
| Apples | 311 | 12 | N/A | <100 | 10 |
| Bananas | >1,200 | 737 | N/A | 490 | 88 |
| Oranges | 48 | 184 | N/A | N/A | 1 |
| Fruits | 161 | 94 | N/A | - | 6 |
(I have posted this in table format, to make it more readable, but the CSV data is at the bottom of this post).
All the CSV files have the same header row. Only the data is different.
I would like to do the following:
Merge all the CSV files together, but only have 1 header row.
Omit any rows where EST. A SE/M (Column 5) contains any of the following data: <100, N/A or -
Notes about the Data
Sometimes the some or even all cells in the CSV file are wrapped in quotation marks.
Other times they are not.
Sometimes the first column (keyword) may contain multiple words or accented characters.
My code so far
This code merges all the CSV files into 1 without only one heading
awk '(NR == 1) || (FNR > 1)' *.csv > ^0-output.csv
This works perfectly.
However, I am not sure how to delete the unwanted rows after the merge.
So far I have this:
awk '$5 !~ /(<100|N\/A|-)/' ^0-output.csv > ^0-output.csv
But when I use this code, it just produces a blank file.
Plus, I am not sure if there is a way to integrate it in the first line, so it does everything with a single command.
Notes
Here is how the data looks in CSV format
Sample1.csv
KEYWORD,NUMBER OF COMPS,AVGE M E (K),GS/M,EST. A SE/M,C CORE
Apples,311,12,N/A,<100,10
Bananas,">1,200",737,N/A,490,88
Oranges,48,184,N/A,N/A,1
Fruits,161,94,N/A,-,63
Sample2.csv
KEYWORD,NUMBER OF COMPS,AVGE M E (K),GS/M,EST. A SE/M,C CORE
Dino,588,67,N/A,888,234
Thunder,">1,200",211,N/A,<100,77
Ninja,95,37,N/A,-,878
Sample3.csv
KEYWORD,NUMBER OF COMPS,AVGE M E (K),GS/M,EST. A SE/M,C CORE
Blur,84,2454,N/A,-,234
Sample4.csv
"KEYWORD","NUMBER OF COMPS","AVGE M E (K)","GS/M","EST. A SE/M","C CORE"
"hedgehog rolls ròund",32,481,N/A,"878",13
"Clever Fox jumps Hîgh",233,83,N/A,"<100",12
"Bear à lot",122,35,N/A,"-",11
"kitten hîgh life","121","673","32","N/A","15"
Please note: The actual files that the finished script will be used on will have a variety of file names. They will NOT always follow the pattern of sample 1, sample 2 etc.
Expected Output
Expected output: (CSV format)
KEYWORD,NUMBER OF COMPS,AVGE M E (K),GS/M,EST. A SE/M,C CORE
Bananas,">1,200",737,N/A,490,88
Dino,588,67,N/A,888,234
"hedgehog rolls ròund",32,481,N/A,"878",13
(Note: It doesn't matter if the expected output keeps the wrapping quote marks as the final CSV file is opened in Apple Numbers)
Expected output: (Readable format)
| KEYWORD | NUMBER OF COMPS | AVGE M E (K) | GS/M | EST. A SE/M | C CORE |
|---------|-----------------|--------------|------|-------------|--------|
| Bananas | >1,200 | 737 | N/A | 490 | 88 |
| Dino | 588 | 67 | N/A | 888 | 234 |
| hedgehog rolls ròund | 588 | 67 | N/A | 888 | 234 |
Environment:
I am using Mac OS X 10.14.6. I am unable to install other versions of awk.

Answer 1

You may just add merge 2 conditions into one using && :
awk -F, 'NR==1 || (FNR>1 && $5 !~ /^(<100|N\/A|-)$/)' *.csv > output.csv
Here $5 !~ /^(<100|N\/A|-)$/) will skip a row if $5 is <100 or - or N/A. It is important to use regex anchors ^ and $ to avoid matching unwanted string such as 1000 or AB-123.
It seems you have a comma in double quotes also in file1.csv. In that case following gnu-awk command should work from you:
awk -v FPAT='"[^"]*"|[^,]*' '
NR == 1 || (FNR > 1 && $5 !~ /^(<100|N\/A|-)*$/)' *.csv > output.csv

Answer 2

EDIT: As per OP's comments there could be a comma in between " too, so to handle that its better to use FPAT, written and tested with GNU awk.
awk -v FPAT='[^,]*|"[^"]+"' '
{ sub(/\r$/,"") }
FNR==1{
if(NR==1){ print }
next
}
$5=="<100"||$5=="N/A"||$5=="-"{
next
}
1
' *.csv
Could you please try following, written and tested with GNU awk on shown samples only.
awk '
BEGIN{
FS=OFS=","
}
FNR==1{
if(NR==1){ print }
next
}
$5=="<100"||$5=="N/A"||$5=="-"{ next }
1
' *.csv
OR in case your values can contain something else also and you want to use regex to match the values which you want to neglect then try following.
awk '
BEGIN{
FS=OFS=","
}
FNR==1{
if(NR==1){ print }
next
}
$5~/<100/ || $5~/N\/A/ || $5~/-/{ next }
1
' *.csv
Explanation: Adding detailed explanation for above.
awk ' ##Starting awk program from here.
BEGIN{ ##Starting BEGIN section of this program from here.
FS=OFS="," ##Setting field separator as comma here.
}
FNR==1{ ##Checking condition if its firt line of current Input_file then do following.
if(NR==1){ print } ##If its very first line of very first Input_file then print that line.
next ##next will skip all further statements from here.
}
$5=="<100"||$5=="N/A"||$5=="-"{ next } ##Checking condition if 5th field contains either <100 OR N/A OR - then skip all further statements.
1 ##awk'sh way to print the current line.
' *.csv ##Passing all .csv files to awk program from here.

Answer 3

It looks to me like you're only interested in testing the 2nd-last field and neither that nor the last field can contain commas so just count field numbers from the end instead of from the beginning of each line and then you don't care whether earlier fields contain commas or not. Given that, this will work using any awk:
$ awk -F',' '(NR==1) || (FNR>1 && $(NF-1)!~/^"?(<100|N\/A|-)"?$/)' *.csv
KEYWORD,NUMBER OF COMPS,AVGE M E (K),GS/M,EST. A SE/M,C CORE
Bananas,">1,200",737,N/A,490,88
Dino,588,67,N/A,888,234
"hedgehog rolls ròund",32,481,N/A,"878",13