Changing second column in csv conditionally
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im new to bash and would like some help.
I have a csv that looks like:
data/train/4/36280.png,four
data/train/2/10317.png,two
data/train/2/57890.png,two
data/train/1/53448.png,one
data/train/8/58233.png,eight
data/train/4/23599.png,four
data/train/2/35051.png,two
data/train/1/12323.png,one
data/train/9/18562.png,nine
data/train/8/46629.png,eight
data/train/7/1746.png,seven
where first column is path and second is class. I would like to change the second column conditionally. In pseudo code I want something like: If second column "four" change it to the next rows class.
So far I´ve tried just to see if I can change a class to another, but without success. awk '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv gives me the same csv.
Basically I would like a script that gives me following output csv:
data/train/4/36280.png,seven
data/train/2/10317.png,four
data/train/2/57890.png,two
data/train/1/53448.png,two
data/train/8/58233.png,one
data/train/4/23599.png,eight
data/train/2/35051.png,four
data/train/1/12323.png,two
data/train/9/18562.png,one
data/train/8/46629.png,nine
data/train/7/1746.png,eight
command-line bash awk csv
edited 19 hours ago
RoVo
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
im new to bash and would like some help.
I have a csv that looks like:
data/train/4/36280.png,four
data/train/2/10317.png,two
data/train/2/57890.png,two
data/train/1/53448.png,one
data/train/8/58233.png,eight
data/train/4/23599.png,four
data/train/2/35051.png,two
data/train/1/12323.png,one
data/train/9/18562.png,nine
data/train/8/46629.png,eight
data/train/7/1746.png,seven
where first column is path and second is class. I would like to change the second column conditionally. In pseudo code I want something like: If second column "four" change it to the next rows class.
So far I´ve tried just to see if I can change a class to another, but without success. awk '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv gives me the same csv.
Basically I would like a script that gives me following output csv:
data/train/4/36280.png,seven
data/train/2/10317.png,four
data/train/2/57890.png,two
data/train/1/53448.png,two
data/train/8/58233.png,one
data/train/4/23599.png,eight
data/train/2/35051.png,four
data/train/1/12323.png,two
data/train/9/18562.png,one
data/train/8/46629.png,nine
data/train/7/1746.png,eight
command-line bash awk csv
edited 19 hours ago
RoVo
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the-Fcommand line option, or by settingFS=","in aBEGINrule.
– steeldriver
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago
add a comment |
im new to bash and would like some help.
I have a csv that looks like:
data/train/4/36280.png,four
data/train/2/10317.png,two
data/train/2/57890.png,two
data/train/1/53448.png,one
data/train/8/58233.png,eight
data/train/4/23599.png,four
data/train/2/35051.png,two
data/train/1/12323.png,one
data/train/9/18562.png,nine
data/train/8/46629.png,eight
data/train/7/1746.png,seven
where first column is path and second is class. I would like to change the second column conditionally. In pseudo code I want something like: If second column "four" change it to the next rows class.
So far I´ve tried just to see if I can change a class to another, but without success. awk '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv gives me the same csv.
Basically I would like a script that gives me following output csv:
data/train/4/36280.png,seven
data/train/2/10317.png,four
data/train/2/57890.png,two
data/train/1/53448.png,two
data/train/8/58233.png,one
data/train/4/23599.png,eight
data/train/2/35051.png,four
data/train/1/12323.png,two
data/train/9/18562.png,one
data/train/8/46629.png,nine
data/train/7/1746.png,eight
command-line bash awk csv
edited 19 hours ago
RoVo
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
im new to bash and would like some help.
I have a csv that looks like:
data/train/4/36280.png,four
data/train/2/10317.png,two
data/train/2/57890.png,two
data/train/1/53448.png,one
data/train/8/58233.png,eight
data/train/4/23599.png,four
data/train/2/35051.png,two
data/train/1/12323.png,one
data/train/9/18562.png,nine
data/train/8/46629.png,eight
data/train/7/1746.png,seven
where first column is path and second is class. I would like to change the second column conditionally. In pseudo code I want something like: If second column "four" change it to the next rows class.
So far I´ve tried just to see if I can change a class to another, but without success. awk '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv gives me the same csv.
Basically I would like a script that gives me following output csv:
data/train/4/36280.png,seven
data/train/2/10317.png,four
data/train/2/57890.png,two
data/train/1/53448.png,two
data/train/8/58233.png,one
data/train/4/23599.png,eight
data/train/2/35051.png,four
data/train/1/12323.png,two
data/train/9/18562.png,one
data/train/8/46629.png,nine
data/train/7/1746.png,eight
command-line bash awk csv
command-line bash awk csv
edited 19 hours ago
RoVo
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 19 hours ago
RoVo
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 19 hours ago
RoVo
8,1411943
edited 19 hours ago
RoVo
8,1411943
edited 19 hours ago
RoVo
8,1411943
8,1411943
asked 20 hours ago
iKnowItAlliKnowItAll
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 20 hours ago
iKnowItAlliKnowItAll
233
asked 20 hours ago
iKnowItAlliKnowItAll
233
233
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
iKnowItAll is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the-Fcommand line option, or by settingFS=","in aBEGINrule.
– steeldriver
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago
add a comment |
The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the-Fcommand line option, or by settingFS=","in aBEGINrule.
– steeldriver
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago
The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the
-F command line option, or by setting FS="," in a BEGIN rule.– steeldriver
20 hours ago
The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the
-F command line option, or by setting FS="," in a BEGIN rule.– steeldriver
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago
add a comment |
1 Answer
1
active
oldest
votes
bash solution:
readarray -t filename < <(cut -d ',' -f1 train.csv)
readarray -t class < <(cut -d ',' -f2 train.csv)
for (( i=0; i<${#filename[@]}; i++ )); do
printf '%s,%sn' "${filename[$i]}" "${class[$((i-1))]}";
done > new_file.csv
Equivalent awk solution:
awk -F, '
{
filename[NR]=$1
class[NR]=$2
}
END {
OFS=","
print filename[1],class[NR]
for (i=2;i<=NR;i++) {
print filename[i],class[i-1]
}
}
' train.csv > new_file.csv
Both solutions first read the lines into arrays filename and class. Only difference is that the bash array starts with 0, the awk array with 1.
Then, we loop over the arrays and print the desired output. In the awk solution, we need to treat the first line separately as, unlike in bash, array[-1] does not return the last element.
The awk solution is a bit faster.
answered 19 hours ago
RoVoRoVo
8,1411943
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
add a comment |
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1 Answer
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1 Answer
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active
oldest
votes
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oldest
votes
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oldest
votes
bash solution:
readarray -t filename < <(cut -d ',' -f1 train.csv)
readarray -t class < <(cut -d ',' -f2 train.csv)
for (( i=0; i<${#filename[@]}; i++ )); do
printf '%s,%sn' "${filename[$i]}" "${class[$((i-1))]}";
done > new_file.csv
Equivalent awk solution:
awk -F, '
{
filename[NR]=$1
class[NR]=$2
}
END {
OFS=","
print filename[1],class[NR]
for (i=2;i<=NR;i++) {
print filename[i],class[i-1]
}
}
' train.csv > new_file.csv
Both solutions first read the lines into arrays filename and class. Only difference is that the bash array starts with 0, the awk array with 1.
Then, we loop over the arrays and print the desired output. In the awk solution, we need to treat the first line separately as, unlike in bash, array[-1] does not return the last element.
The awk solution is a bit faster.
answered 19 hours ago
RoVoRoVo
8,1411943
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
add a comment |
bash solution:
readarray -t filename < <(cut -d ',' -f1 train.csv)
readarray -t class < <(cut -d ',' -f2 train.csv)
for (( i=0; i<${#filename[@]}; i++ )); do
printf '%s,%sn' "${filename[$i]}" "${class[$((i-1))]}";
done > new_file.csv
Equivalent awk solution:
awk -F, '
{
filename[NR]=$1
class[NR]=$2
}
END {
OFS=","
print filename[1],class[NR]
for (i=2;i<=NR;i++) {
print filename[i],class[i-1]
}
}
' train.csv > new_file.csv
Both solutions first read the lines into arrays filename and class. Only difference is that the bash array starts with 0, the awk array with 1.
Then, we loop over the arrays and print the desired output. In the awk solution, we need to treat the first line separately as, unlike in bash, array[-1] does not return the last element.
The awk solution is a bit faster.
answered 19 hours ago
RoVoRoVo
8,1411943
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
add a comment |
bash solution:
readarray -t filename < <(cut -d ',' -f1 train.csv)
readarray -t class < <(cut -d ',' -f2 train.csv)
for (( i=0; i<${#filename[@]}; i++ )); do
printf '%s,%sn' "${filename[$i]}" "${class[$((i-1))]}";
done > new_file.csv
Equivalent awk solution:
awk -F, '
{
filename[NR]=$1
class[NR]=$2
}
END {
OFS=","
print filename[1],class[NR]
for (i=2;i<=NR;i++) {
print filename[i],class[i-1]
}
}
' train.csv > new_file.csv
Both solutions first read the lines into arrays filename and class. Only difference is that the bash array starts with 0, the awk array with 1.
Then, we loop over the arrays and print the desired output. In the awk solution, we need to treat the first line separately as, unlike in bash, array[-1] does not return the last element.
The awk solution is a bit faster.
answered 19 hours ago
RoVoRoVo
8,1411943
bash solution:
readarray -t filename < <(cut -d ',' -f1 train.csv)
readarray -t class < <(cut -d ',' -f2 train.csv)
for (( i=0; i<${#filename[@]}; i++ )); do
printf '%s,%sn' "${filename[$i]}" "${class[$((i-1))]}";
done > new_file.csv
Equivalent awk solution:
awk -F, '
{
filename[NR]=$1
class[NR]=$2
}
END {
OFS=","
print filename[1],class[NR]
for (i=2;i<=NR;i++) {
print filename[i],class[i-1]
}
}
' train.csv > new_file.csv
Both solutions first read the lines into arrays filename and class. Only difference is that the bash array starts with 0, the awk array with 1.
Then, we loop over the arrays and print the desired output. In the awk solution, we need to treat the first line separately as, unlike in bash, array[-1] does not return the last element.
The awk solution is a bit faster.
answered 19 hours ago
RoVoRoVo
8,1411943
edited 19 hours ago
answered 19 hours ago
RoVoRoVo
8,1411943
answered 19 hours ago
RoVoRoVo
8,1411943
answered 19 hours ago
RoVoRoVo
8,1411943
8,1411943
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
add a comment |
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
I tried it and it looks great! Could I ask how I would save this to a new CSV? I guess its putting > new_file.csv at the end maybe?
– iKnowItAll
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
exactly, added to the answer
– RoVo
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
Thanks alot!! Works great!
– iKnowItAll
19 hours ago
add a comment |
iKnowItAll is a new contributor. Be nice, and check out our Code of Conduct.
iKnowItAll is a new contributor. Be nice, and check out our Code of Conduct.
iKnowItAll is a new contributor. Be nice, and check out our Code of Conduct.
iKnowItAll is a new contributor. Be nice, and check out our Code of Conduct.
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The default field separator in awk is whitespace; if you have comma separated data, you will need to set the separator accordingly - either with the
-Fcommand line option, or by settingFS=","in aBEGINrule.– steeldriver
20 hours ago
What is "the next rows class" ? Could you please edit your question and add an example output?
– RoVo
20 hours ago
You mean like `awk FS="," '{ if ($2 == "zero") $2="one"; print $0 }' train.csv > new_file.csv´ Next row class for line 1 is line 2, column 2. I basically want to shuffle the class in an easy way
– iKnowItAll
20 hours ago