Split and compare in awk - linux

I want to split and comparison in awk command.
Input file (tab-delimited)
1 aaa 1|3
2 bbb 3|3
3 ccc 0|2
Filtration
First column value > 1
First value of third column value splitted by "|" > 2
Process
Compare first column value if bigger than 1
Split third column value by "|"
Compare first value of the third column if bigger than 2
Print if the first value bigger than 2 only
Command line (example)
awk -F "\t" '{if($1>1 && ....?) print}' file
Output
2 bbb 3|3
Please let me know command line for above processing.

You can set the field separator to either tab or pipe and check the 1st and 3rd values:
awk -F'\t|\\|' '$1>1 && $3>2' file
or
awk -F"\t|\\\\|" '$1>1 && $3>2' file
You can read about all this character escaping in this comprehensive answer by Ed Morton in awk: fatal: Invalid regular expression when setting multiple field separators.
Otherwise, you can split the 3rd field and check the value of the first slice:
awk -F"\t" '{split($3,a,"|")} $1>1 && a[1]>=2' file

Related

How to insert a column at the start of a txt file using awk?

How to insert a column at the start of a txt file running from 1 to 2059 which corresponds to the number of rows I have in my file using awk. I know the command will be something like this:
awk '{$1=" "}1' File
Not sure what to put between the speech-marks 1-2059?
I also want to include a header in the header row so 1 should only go in the second row technically.
**ID** Heading1
RQ1293939 -7.0494
RG293I32SJ -903.6868
RQ19238983 -0899977
rq747585950 988349303
FID **ID** Heading1
1 RQ1293939 -7.0494
2 RG293I32SJ -903.6868
3 RQ19238983 -0899977
4 rq747585950 988349303
So I need to insert the FID with 1 - 2059 running down the first column
What you show does not work, it just replaces the first field ($1) with a space and prints the result. If you do not have empty lines try:
awk 'NR==1 {print "FID\t" $0; next} {print NR-1 "\t" $0}' File
Explanations:
NR is the awk variable that counts the records (the lines, in our case), starting from 1. So NR==1 is a condition that holds only when awk processes the first line. In this case the action block says to print FID, a tab (\t), the original line ($0), and then move to next line.
The second action block is executed only if the first one has not been executed (due to the final next statement). It prints NR-1, that is the line number minus one, a tab, and the original line.
If you have empty lines and you want to skip them we will need a counter variable to keep track of the current non-empty line number:
awk 'NR==1 {print "FID\t" $0; next} NF==0 {print; next} {print ++cnt "\t" $0}' File
Explanations:
NF is the awk variable that counts the fields in a record (the space-separated words, in our case). So NF==0 is a condition that holds only on empty lines (or lines that contain only spaces). In this case the action block says to print the empty line and move to the next.
The last action block is executed only if none of the two others have been executed (due to their final next statement). It increments the cnt variable, prints it, prints a tab, and prints the original line.
Uninitialized awk variables (like cnt in our example) take value 0 when they are used for the first time as a number. ++cnt increments variable cnt before its value is used by the print command. So the first time this block is executed cnt takes value 1 before being printed. Note that cnt++ would increment after the printing.
Assuming you don't really have a blank row between your header line and the rest of your data:
awk '{print (NR>1 ? NR-1 : "FID"), $0}' file
Use awk -v OFS='\t' '...' file if you want the output to be tab-separated or pipe it to column -t if you want it visually tabular.

Print a column without 1st item of that column

Good night everybody, i want to print a column without printing the 1st item of that column.
I want print the 4th column of this csv file:
ID;Curso;AnoNasc;MediaAcesso;Salario;IndiceSatisfacao
1;Psicologia;1994;18;750;3
2;Psicologia;1992;17;754;4
3;Psicologia;1991;13;780;4
4;Psicologia;1993;11;900;4
So i do this:
system("awk -F ';' '{print $4}' DBcursos.csv > ficha02exer08-mediaacesso.dat");
But this print:
MediaAcesso
18
17
13
11
But i only want the numbers, so i want to print all except the first line (MediaAcesso), how can i do this? Can i do this with AWK?
Thank you!
Don't think of it as skipping the first element of a column, you just want to skip processing the entire first row of the file. So check the record number and only process records after that one.
awk -F ';' 'NR > 1 {print $4}' DBcursos.csv > ficha02exer08-mediaacesso.dat

Extract substring from first column

I have a large text file with 2 columns. The first column is large and complicated, but contains a name="..." portion. The second column is just a number.
How can I produce a text file such that the first column contains ONLY the name, but the second column stays the same and shows the number? Basically, I want to extract a substring from the first column only AND have the 2nd column stay unaltered.
Sample data:
application{id="1821", name="app-name_01"} 0
application{id="1822", name="myapp-02", optionalFlag="false"} 1
application{id="1823", optionalFlag="false", name="app_name_public"} 3
...
So the result file would be something like this
app-name_01 0
myapp-02 1
app_name_public 3
...
If your actual Input_file is same as the shown sample then following code may help you in same.
awk '{sub(/.*name=\"/,"");sub(/\".* /," ")} 1' Input_file
Output will be as follows.
app-name_01 0
myapp-02 1
app_name_public 3
Using GNU awk
$ awk 'match($0,/name="([^"]*)"/,a){print a[1],$NF}' infile
app-name_01 0
myapp-02 1
app_name_public 3
Non-Gawk
awk 'match($0,/name="([^"]*)"/){t=substr($0,RSTART,RLENGTH);gsub(/name=|"/,"",t);print t,$NF}' infile
app-name_01 0
myapp-02 1
app_name_public 3
Input:
$ cat infile
application{id="1821", name="app-name_01"} 0
application{id="1822", name="myapp-02", optionalFlag="false"} 1
application{id="1823", optionalFlag="false", name="app_name_public"} 3
...
Here's a sed solution:
sed -r 's/.*name="([^"]+).* ([0-9]+)$/\1 \2/g' Input_file
Explanation:
With the parantheses your store in groups what's inbetween.
First group is everything after name=" till the first ". [^"] means "not a double-quote".
Second group is simply "one or more numbers at the end of the line preceeded with a space".

Subtract a constant number from a column

I have two large files (~10GB) as follows:
file1.csv
name,id,dob,year,age,score
Mike,1,2014-01-01,2016,2,20
Ellen,2, 2012-01-01,2016,4,35
.
.
file2.csv
id,course_name,course_id
1,math,101
1,physics,102
1,chemistry,103
2,math,101
2,physics,102
2,chemistry,103
.
.
I want to subtract 1 from the "id" columns of these files:
file1_updated.csv
name,id,dob,year,age,score
Mike,0,2014-01-01,2016,2,20
Ellen,0, 2012-01-01,2016,4,35
file2_updated.csv
id,course_name,course_id
0,math,101
0,physics,102
0,chemistry,103
1,math,101
1,physics,102
1,chemistry,103
I have tried awk '{print ($1 - 1) "," $0}' file2.csv, but did not get the correct result:
-1,id,course_name,course_id
0,1,math,101
0,1,physics,102
0,1,chemistry,103
1,2,math,101
1,2,physics,102
1,2,chemistry,103
You've added an extra column in your attempt. Instead set your first field $1 to $1-1:
awk -F"," 'BEGIN{OFS=","} {$1=$1-1;print $0}' file2.csv
That semicolon separates the commands. We set the delimiter to comma (-F",") and the Output Field Seperator to comma BEGIN{OFS=","}. The first command to subtract 1 from the first field executes first, then the print command executes second, so the entire record, $0, will now contain the new $1 value when it's printed.
It might be helpful to only subtract 1 from records that are not your header. So you can add a condition to the first command:
awk -F"," 'BEGIN{OFS=","} NR>1{$1=$1-1} {print $0}' file2.csv
Now we only subtract when the record number (NR) is greater than 1. Then we just print the entire record.

Separate comma delimited cells to new rows with shell script

I have a table with comma delimited columns and I want to separate the comma delimited values in my specified column to new rows. For example, the given table is
Name Start Name2
A 1,2 X,a
B 5 Y,b
C 6,7,8 Z,c
And I need to separate the comma delimited values in column 2 to get the table below
Name Start Name2
A 1 X,a
A 2 X,a
B 5 Y,b
C 6 Z,c
C 7 Z,c
C 8 Z,c
I am wondering if there is any solution with shell script, so that I can create a workflow pipe.
Note: the original table may contain more than 3 columns.
Assuming the format of your input and output does not change:
awk 'BEGIN{FS="[ ,]"} {print $1, $2, $NF; print $1, $3, $NF}' input_file
Input:
input_file:
A 1,2 X
B 5,6 Y
Output:
A 1 X
A 2 X
B 5 Y
B 6 Y
Explanation:
awk: invoke awk, a tool for manipulating lines (records) and fields
'...': content enclosed by single-quotes are supplied to awk as instructions
'BEGIN{FS="[ ,]"}: before reading any lines, tell awk to use both space and comma as delimiters; FS stands for Field Separator.
{print $1, $2, $NF; print $1, $3, $NF}: For each input line read, print the 1st, 2nd and last field on one line, and then print the 1st, 3rd, and last field on the next line. NF stands for Number of Fields, so $NF is the last field.
input_file: supply the name of the input file to awk as an argument.
In response to updated input format:
awk 'BEGIN{FS="[ ,]"} {print $1, $2, $4","$5; print $1, $3, $4","$5}' input_file
After Runner's modification of the original question another approach might look like this:
#!/bin/sh
# Usage $0 <file> <column>
#
FILE="${1}"
COL="${2}"
# tokens separated by linebreaks
IFS="
"
for LINE in `cat ${FILE}`; do
# get number of columns
COLS="`echo ${LINE} | awk '{print NF}'`"
# get actual field by COL, this contains the keys to be splitted into individual lines
# replace comma with newline to "reuse" newline field separator in IFS
KEYS="`echo ${LINE} | cut -d' ' -f${COL}-${COL} | tr ',' '\n'`"
COLB=$(( ${COL} - 1 ))
COLA=$(( ${COL} + 1 ))
# get text from columns before and after actual field
if [ ${COLB} -gt 0 ]; then
BEFORE="`echo ${LINE} | cut -d' ' -f1-${COLB}` "
else
BEFORE=""
fi
AFTER=" `echo ${LINE} | cut -d' ' -f${COLA}-`"
# echo "-A: $COLA ($AFTER) | B: $COLB ($BEFORE)-"
# iterate keys and re-build original line
for KEY in ${KEYS}; do
echo "${BEFORE}${KEY}${AFTER}"
done
done
With this shell file you might do what you want. This will split column 2 into multiple lines.
./script.sh input.txt 2
If you'd like to pass inputs though standard input using pipes (e.g. to split multiple columns in one go) you could change the 6. line to:
if [ "${1}" == "-" ]; then
FILE="/dev/stdin"
else
FILE="${1}"
fi
And run it this way:
./script.sh input.txt 1 | ./script.sh - 2 | ./script.sh - 3
Note that cut is very sensitiv about the field separators. Soif the line starts with a space character, column 1 would be "" (empty). If the fields were separated by amixture of spaces and tabs this script would have other issues too. In this case (as explained above) filtering the input resource (so that fields are only separated by one space character) should do it. If this is not possible or the data in each column contains space characters too, the script might get more complicated.

Resources