使用awk循环输入字符串中的字符

Question

信不信由你,我找不到我认为这个基本问题的答案.

在awk中,我如何逐个字符地循环输入字符串？假设我只想将它们打印出来.我可以访问一个数组吗？或者我需要使用substr？

基本上,像:

echo "here is a string" | awk '
{ for(i=0; i<[length of input string]; i++) 
    printf [value at index i in array x]; 
}'

坦率地说,我很尴尬.

Answer 1

您可以使用以下命令将字符串转换为数组split:

echo "here is a string" | awk '
{ 
  split($0, chars, "")
  for (i=1; i <= length($0); i++) {
    printf("%s\n", chars[i])
  }
}'

这将垂直打印字符,每行一个.

Answer 2

默认情况下,在awk该Field Separator (FS)IS space或tabs.既然你提到你想要遍历每个字符而不是字,我们将不得不重新定义FS.像这样的东西 -

[jaypal:~/Temp] echo "here is a string" | awk -v FS="" '
{for (i=1;i<=NF;i++) printf "Character "i": " $i"\n"}' 
Character 1: h
Character 2: e
Character 3: r
Character 4: e
Character 5:  
Character 6: i
Character 7: s
Character 8:  
Character 9: a
Character 10:  
Character 11: s
Character 12: t
Character 13: r
Character 14: i
Character 15: n
Character 16: g

Answer 3

并非所有awk实现都支持上述解决方案.在这种情况下,您可以使用substr:

echo here is a string | awk '{
  for (i=0; ++i <= length($0);) 
    printf "%s\n", substr($0, i, 1)
  }'

PS在一些awk实现中,不带参数的长度默认为$ 0,即长度和长度($ 0)是等价的.