[英]awk to fill from previous value then delete
如果第二列( $2=="")
為null,則考慮該行,然后將值打印為$1
,其余各行打印,直到下一第二列為null ($2=="")
為止。 然后需要delete
第二列為空的所有行( $2=="")
file.csv
Name_Subject,Marks,Desc,Details
Adam,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
Benn,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
Science,30,zzz,zzz
Zak,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
output.csv
Name,Subject,Marks,Desc,Details
Adam,English,10,xxx,xxx
Adam,Maths,20,yyy,yyy
Benn,English,10,xxx,xxx
Benn,Maths,20,yyy,yyy
Benn,Science,30,zzz,zzz
Zak,English,10,xxx,xxx
Zak,Maths,20,yyy,yyy
我已經嘗試過像下面的命令一樣沒有成功...
awk -F, 'NR==1{print; next} {if($2 == ""){$2=A}} {A=$2} 1' file.csv
編輯#1
實際文件包含,數據之間整行中的某些行為空。 對於此實例,它正在填充空值,但希望捕獲先前的非空值。
file.csv
Name_Subject,Marks,Desc,Details
Adam,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
Benn,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
Science,30,zzz,zzz
,,,
,,,
History,40,zzz,zzz
Zak,,,
English,10,xxx,xxx
Maths,20,yyy,yyy
輸出#1
Name,Subject,Marks,Desc,Details
Adam,English,10,xxx,xxx
Adam,Maths,20,yyy,yyy
Benn,English,10,xxx,xxx
Benn,Maths,20,yyy,yyy
Benn,Science,30,zzz,zzz
,History,40,zzz,zzz
Zak,English,10,xxx,xxx
Zak,Maths,20,yyy,yyy
$ awk '
BEGIN { FS=OFS="," }
NR==1 { split($1,f,/_/); name=f[1]; $1=f[2] }
$2=="" { name=$1; next }
{ print name, $0 }
' file
Name,Subject,Marks,Desc,Details
Adam,English,10,xxx,xxx
Adam,Maths,20,yyy,yyy
Benn,English,10,xxx,xxx
Benn,Maths,20,yyy,yyy
Benn,Science,30,zzz,zzz
Zak,English,10,xxx,xxx
Zak,Maths,20,yyy,yyy
簡短的awk方法:
awk -F, 'NR==1;$1==""{next}NR>1 && $2==""{ f=$1; next }f{ print f,$0 }' OFS=',' file
輸出:
Name_Subject,Marks,Desc,Details
Adam,English,10,xxx,xxx
Adam,Maths,20,yyy,yyy
Benn,English,10,xxx,xxx
Benn,Maths,20,yyy,yyy
Benn,Science,30,zzz,zzz
Benn,History,40,zzz,zzz
Zak,English,10,xxx,xxx
Zak,Maths,20,yyy,yyy
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