awk split问题

cclxpp123

1. [r@r ~]$ head -1 d
   
2. Hyper                 Text     Transfer Protocal
   
3. [r@r ~]$ awk 'NR==1{n=split($0,a," ");for(i=1;i<=n;++i){split(a[i],b,"");printf b[1]}}' d
   
4. HTTP
   
5. [r@r ~]$ awk 'NR==1{split($0,a," ");for(i in a){split(a[i],b,"");printf b[1]}}' d
   
6. PHTT
   

复制代码

提取首字母，为何下面的顺序会不一样？

fh21_xuejinlian

for(i in a)是无序的

fh21_xuejinlian

awk 'NR==1{split($0,a," ");for(i=1;i<=asorti(a,c);i++){split(a[c[i]],b,"");printf b[1]};print ""}' file

cd_ly

awk '{for(i=1;i<=NF;i++){split($i,a,"");printf a[1]}print ""}' file

cd_ly

awk '{for(i=1;i<=NF;i++){printf substr($i,1,1)}print ""}' file