sed replace text between comma - awk

Question

I have csv files that need to be changed f -> 0 and t -> 1 only between commas for every single csv if it matches. From:
,t,t,f,f,a,t,f,t,f,f,t,f,
tftf
to:
,1,1,0,0,a,1,0,1,0,0,1,0,
tftf
Works this way, but want to know better way that could reduce the replacing time consume
for i in 1 2 3 4 5 6
do
echo "converting tables for mariaDB"
find ./ -type f -name "*.csv" -print0 | xargs -0 sed -i 's/\,t\,/\,1\,/g'
find ./ -type f -name "*.csv" -print0 | xargs -0 sed -i 's/\,f\,/\,0\,/g'
echo "$i time(s) changed "
done
I except , one single command will change the line

Answer 1

Could you please try following. Though it is not perfect solution but would be simplest use it in case you don't have gawk's latest version where -inplace edit option is present.
for file in *.csv
awk '{gsub(/,t,/,",1,");gsub(/,f,/,",0,");gsub(/,t,/,",1,");gsub(/,f,/,",0,")} 1' "$file" > temp && mv temp"$file"
done
OR
for file in *.csv
awk -v t_val="1" -v f_val="0" 'BEGIN{FS=OFS=","}{for(i=2;i<NF;i++){$i=($i=="t"?t_val:$i=="f"?f_val:$i)}} 1' "$file" > temp && mv temp "$file"
done
2nd solution: Using gawk's latest version where we could save edit into Input_file itself.
gawk -i inplace '{gsub(/,t,/,",1,");gsub(/,f,/,",0,");gsub(/,t,/,",1,");gsub(/,f,/,",0,")} 1' *.csv
OR
gawk -i inplace -v t_val="1" -v f_val="0" 'BEGIN{FS=OFS=","}{for(i=2;i<NF;i++){$i=($i=="t"?t_val:$i=="f"?f_val:$i)}} 1' Input_file

Answer 2

The main problem, in this case, is that a regular expression does not allow overlap when parsing it with sed 's/ere/str/g' or awk '{gsub(ere,str,$0)}'. This comment nicely explains how you can circumvent this in sed using the t<label> command, which means: if a change happened to the pattern space, move to <label>. The comment shows a generic way of doing it. The awk alternative to this rule would be:
$ awk '{while(match($0,ere)) gsub(ere,str)}'
An alternative sed solution in the case of the OP's example could use the following idea:
duplicate all commas. Since we are searching for strings of the form ",t,", this duplication avoid overlap using s.
since no overlap is possible, replace all ",f," with ",0," and all ",t," with ",1,".
We can now revert all duplicated commas again. As no overlap is allowed, sequences like ,,,, will be nicely converted to ,, and not ,
In POSIX sed this looks like:
$ sed -e 's/,/,,/g' -e 's/,f,/,0,/g' \
-e 's/,t,/,1,/g' -e 's/,,/,/g' file > file.tmp
$ mv file.tmp file
With GNU sed we can do it in one go:
$ sed -i 's/,/,,/g;s/,f,/,0,/g;s/,t,/,1,/g;s/,,/,/g' file
With awk, this would look like:
$ awk 'BEGIN{FS=",";OFS=FS FS}
{$1=$1;gsub(/,f,/,",0,");gsub(/,t,/,",1,");gsub(OFS,FS)}1' file > file.tmp
$ mv file.tmp file