I have a .csv where each row corresponds to a person (first column) and attributes with values that are available for that person. I want to extract the names and values a particular attribute for persons where the attribute is available. The doc is structured as follows:
name,attribute1,value1,attribute2,value2,attribute3,value3
joe,height,5.2,weight,178,hair,
james,,,,,,
jesse,weight,165,height,5.3,hair,brown
jerome,hair,black,breakfast,donuts,height,6.8
I want a file that looks like this:
name,attribute,value
joe,height,5.2
jesse,height,5.3
jerome,height,6.8
Using this earlier post, I've tried a few different awk methods but am still having trouble getting both the first column and then whatever column has the desired value for the attribute (say height). For example the following returns everything.
awk -F "height," '{print $1 "," FS$2}' file.csv
I could grep only the rows with height in them, but I'd prefer to do everything in a single line if I can.
You may use this awk:
cat attrib.awk
BEGIN {
FS=OFS=","
print "name,attribute,value"
}
NR > 1 && match($0, k "[^,]+") {
print $1, substr($0, RSTART+1, RLENGTH-1)
}
# then run it as
awk -v k=',height,' -f attrib.awk file
name,attribute,value
joe,height,5.2
jesse,height,5.3
jerome,height,6.8
# or this one
awk -v k=',weight,' -f attrib.awk file
name,attribute,value
joe,weight,178
jesse,weight,165
With your shown samples please try following awk code. Written and tested in GNU awk. Simple explanation would be, using GNU awk and setting RS(record separator) to ^[^,]*,height,[^,]* and then printing RT as per requirement to get expected output.
awk -v RS='^[^,]*,height,[^,]*' 'RT{print RT}' Input_file
I'd suggest a sed one-liner:
sed -n 's/^\([^,]*\).*\(,height,[^,]*\).*/\1\2/p' file.csv
One awk idea:
awk -v attr="height" '
BEGIN { FS=OFS="," }
FNR==1 { print "name", "attribute", "value"; next }
{ for (i=2;i<=NF;i+=2) # loop through even-numbered fields
if ($i == attr) { # if field value is an exact match to the "attr" variable then ...
print $1,$i,$(i+1) # print current name, current field and next field to stdout
next # no need to check rest of current line; skip to next input line
}
}
' file.csv
NOTE: this assumes the input value (height in this example) will match exactly (including same capitalization) with a field in the file
This generates:
name,attribute,value
joe,height,5.2
jesse,height,5.3
jerome,height,6.8
With a perl one-liner:
$ perl -lne '
print "name,attribute,value" if $.==1;
print "$1,$2" if /^(\w+).*(height,\d+\.\d+)/
' file
output
name,attribute,value
joe,height,5.2
jesse,height,5.3
jerome,height,6.8
awk accepts variable-value arguments following a -v flag before the script. Thus, the name of the required attribute can be passed into an awk script using the general pattern:
awk -v attr=attribute1 ' {} ' file.csv
Inside the script, the value of the passed variable is reference by the variable name, in this case attr.
Your criteria are to print column 1, the first column containing the name, the column corresponding to the required header value, and the column immediately after that column (holding the matched values).
Thus, the following script allows you to fish out the column headed "attribute1" and it's next neighbour:
awk -v attr=attribute1 ' BEGIN {FS=","} /attr/{for (i=1;i<=NF;i++) if($i == attr) col=i;} {print $1","$col","$(col+1)} ' data.txt
result:
name,attribute1,value1
joe,height,5.2
james,,
jesse,weight,165
jerome,hair,black
another column (attribute 3):
awk -v attr=attribute3 ' BEGIN {FS=","} /attr/{for (i=1;i<=NF;i++) if($i == attr) col=i;} {print $1","$col","$(col+1)} ' awkNames.txt
result:
name,attribute3,value3
joe,hair,
james,,
jesse,hair,brown
jerome,height,6.8
Just change the value of the -v attr= argument for the required column.
I'm looking to replace the numerical values in a file with a new value provided by me. Can be present in any part of the text, in some cases, it comes across as the third position but is not always necessarily the case. Also to try and save a new version of the file.
original format
A:fdg:user#server:r
A:g:1234:xtcy
A:d:1111:xtcy
modified format
A:fdg:user#server:rxtTncC
A:g:replaced_value:xtcy
A:d:replaced_value:xtcy
bash line command with awk:
awk -v newValue="newVALUE" 'BEGIN{FS=OFS=":"} /:.:.*:/ && ~/^[0-9]+$/{~=newValue} 1' original_file.txt > replaced_file.txt
You can simply use sed instead of awk:
sed -E 's/\b[0-9]+\b/replaced_value/g' /path/to/infile > /path/to/outfile
Here is an awk that asks you for replacement values for each numerical value it meets:
$ awk '
BEGIN {
FS=OFS=":" # delimiters
}
{
for(i=1;i<=NF;i++) # loop all fields
if($i~/^[0-9]+$/) { # if numerical value found
printf "Provide replacement value for %d: ",$i > "/dev/stderr"
getline $i < "/dev/stdin" # ask for a replacement
}
}1' file_in > file_out # write output to a new file
I would use GNU AWK for this task following way, let file.txt content be
A:fdg:user#server:rxtTncC
A:g:1234:xtcy
A:d:1111:xtcy
then
awk 'BEGIN{newvalue="replacement"}{gsub(/[[:digit:]]+/,newvalue);print}' file.txt
output
A:fdg:user#server:rxtTncC
A:g:replacement:xtcy
A:d:replacement:xtcy
Explanation: replace one or more digits using newvalue. Disclaimer: I assumed numeric is something consisting solely from digits.
(tested in gawk 4.2.1)
How about
awk -F : '$3 ~ /^[0-9]+$/ { $3 = "new value"} {print}' original_file >replaced_file
?
IE:
File:
1234:abcd
1234:930
1234:999999
194:keee
194:284
194:222222
Result:
1234:abcd:930:999999
194:kee:284:222222
I have exhausted my brain to the best of my knowledge and can't come up with a way. Sorry to bother you guys!
$ awk -F: '$1==last {printf ":%s",$2; next} NR>1 {print "";} {last=$1; printf "%s",$0;} END{print "";}' file
1234:abcd:930:999999
194:keee:284:222222
How it works
-F:
This tells awk to use a : as the field separator.
$1==last {printf ":%s",$2; next}
If the first field of this line is the same as the first field of the last line, print a colon followed by field 2. Then, skip the rest of the commands and start over with the next line.
NR>1 {print "";}
If we get here, that means that this line has a new not-seen-before value of the first field. If this not the first line, we finish the last line by printing a newline character.
{last=$1; printf "%s",$0;}
Update the variable last with the new value of field 1. Then, print this line.
END{print "";}
After we reach the end of the file, print one last newline character.
Combining non-consecutive lines
Consider this test file:
$ cat testfile2
3:abcd
4:abcd
10:123
3:999
4:999
10:123
Apply this awk script:
$ awk -F: '{a[$1]=a[$1]":"$2;} END{for (x in a) print x ":" substr(a[x],2);}' testfile2
3:abcd:999
4:abcd:999
10:123:123
In this approach, the lines will not necessarily come out in any particular order. If order is important, you may want to pipe this output to sort.
I want to delete lines where the first column does not contain the substring 'cat'.
So if string in col 1 is 'caterpillar', i want to keep it.
awk -F"," '{if($1 != cat) ... }' file.csv
How can i go about doing it?
I want to delete lines where the first column does not contain the substring 'cat'
That can be taken care by this awk:
awk -F, '!index($1, "cat")' file.csv
If that doesn't work then I would suggest you to provide your sample input and expected output in question.
This awk does the job too
awk -F, '$1 ~ /cat/{print}' file.csv
Explanation
-F : "Delimiter"
$1 ~ /cat/ : match pattern cat in field 1
{print} : print
A shorter command is:
awk -F, '$1 ~ "cat"' file.csv
-F is the field delimiter: (,)
$1 ~ "cat" is a (not anchored) regular expression match, match at any position.
As no action has been given, the default: {print} is assumed by awk.