Dynamically edit lists within a csv file - mysql

Question

I have a csv file that looks like that:
col1|col2
1|a
2|g
3|f
1|m
3|k
2|n
2|a
1|d
4|r
3|s
where | separates the columns, and would like to transform it into something homogeneous like:
------------------------
fields > 1 2 3 4
record1 a g f
record2 m n k
record3 d a s r
------------------------
Is there a way to do that? What would be better, using mysql or editing the csv file?

Answer 1

I wrote this, works for your example: gawk is required
awk -F'|' -v RS="" '{for(i=1;i<=NF;i+=2)a[$i]=$(i+1);asorti(a,d);
for(i=1;i<=length(a);i++)printf "%s", a[d[i]]((i==length(a))?"":" ");delete a;delete d;print ""}' file
example:
kent$ cat file
1|a
2|g
3|f
1|m
3|k
2|n
2|a
1|d
4|r
3|s
kent$ awk -F'|' -v RS="" '{for(i=1;i<=NF;i+=2)a[$i]=$(i+1);asorti(a,d);
for(i=1;i<=length(a);i++)printf "%s", a[d[i]]((i==length(a))?"":" ");delete a;delete d;print ""}' file
a g f
m n k
d a s r

Answer 2

Here an awk solution:
BEGIN{
RS=""
FS="\n"
}
FNR==NR&&FNR>1{
for (i=1;i<=NF;i++) {
split($i,d,"|")
if (d[1] > max)
max = d[1]
}
next
}
FNR>1&&!header{
printf "%s\t","fields >"
for (i=1;i<=max;i++)
printf "%s\t",i
print ""
header=1
}
FNR>1{
printf "record%s\t\t",FNR-1
for (i=1;i<=NF;i++) {
split($i,d,"|")
val[d[1]] = d[2]
}
for (i=1;i<=max;i++)
printf "%s\t",val[i]?val[i]:"NULL"
print ""
delete val
}
Save as script.awk and run like (notice it uses a two pass approach so you need to give the file twice):
$ awk -f script.awk file file
fields > 1 2 3 4
record1 a g f NULL
record2 m n k NULL
record3 d a s r
Adding the line 5|b to the first record in file gives the output:
$ awk -f script.awk file file
fields > 1 2 3 4 5
record1 a g f NULL b
record2 m n k NULL NULL
record3 d a s r NULL

Answer 3

$ cat file
col1|col2
1|a
2|g
3|f
5|b
1|m
3|k
2|n
2|a
1|d
4|r
3|s
$
$ awk -f tst.awk file
fields > 1 2 3 4 5
record1 a g f NULL b
record2 m n k NULL NULL
record3 d a s r NULL
$
$ cat tst.awk
BEGIN{ RS=""; FS="\n" }
NR>1 {
++numRecs
for (i=1;i<=NF;i++) {
split($i,fldNr2val,"|")
fldNr = fldNr2val[1]
val = fldNr2val[2]
recNrFldNr2val[numRecs,fldNr] = val
numFlds = (fldNr > numFlds ? fldNr : numFlds)
}
}
END {
printf "fields >"
for (fldNr=1;fldNr<=numFlds;fldNr++) {
printf " %4s", fldNr
}
print ""
for (recNr=1; recNr<=numRecs; recNr++) {
printf "record%d ", recNr
for (fldNr=1;fldNr<=numFlds;fldNr++) {
printf " %4s", ((recNr,fldNr) in recNrFldNr2val ? recNrFldNr2val[recNr,fldNr] : "NULL")
}
print ""
}
}