比较两个文件的两列，如果匹配则打印该行并在第三列打印零
我需要比较我的 file1.txt 和 file2.txt 的第 1 列和第 2 列。如果两列都匹配，则打印 file1.txt 的整行，但 file1.txt 中的一行在 file2.txt 中不存在，还要在输出中打印缺失的行，并在第三列中添加“0”作为其值。
# file1.txt #
AA ZZ
JB CX
CX YZ
BB XX
SU BY
DA XZ
IB KK
XY IK
TY AB
# file2.txt #
AA ZZ 222
JB CX 345
BB XX 3145
DA XZ 876
IB KK 234
XY IK 897
预期输出
# output.txt #
File1.txt
AA ZZ 222
JB CX 345
CX YZ 0
BB XX 3145
SU BY 0
DA XZ 376
IB KK 234
XY IK 897
TY AB 0
我试过这段代码，但不知道如何添加不匹配的行并添加"0"到其中
awk 'BEGIN { while ((getline <"file2.txt") > 0) {REC[$1]=$0}}{print REC[$1]}' < file1.txt > output.txt
回答
使用您显示的样本，您能否尝试以下操作。
awk '
FNR==NR{
arr[$1 OFS $2]
next
}
(($1 OFS $2) in arr){
print
arr1[$1 OFS $2]
}
END{
for(i in arr){
if(!(i in arr1)){
print i,0
}
}
}
' file1.txt file2.txt
说明：为以上添加详细说明。
awk ' ##Starting awk program from here.
FNR==NR{ ##Checking FNR==NR condition which will be TRUE when file1.txt is being read.
arr[$1 OFS $2] ##Creating array with 1st and 2nd field here.
next ##next will skip all further statements from here.
}
(($1 OFS $2) in arr){ ##Checking condition if 1st and 2nd field of file2.txt is present in arr then do following.
print ##Print the current line here.
arr1[$1 OFS $2] ##Creating array arr1 with index of 1st and 2nd fields here.
}
END{ ##Starting END block of this program from here.
for(i in arr){ ##Traversing through arr all elements from here.
if(!(i in arr1)){ ##Checking if an element/key is NOT present in arr1 then do following.
print i,0 ##Printing index and 0 here.
}
}
}
' file1.txt file2.txt ##Mentioning Input_file names here.