string 使用 awk 循环输入字符串中的字符
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loop over characters in input string using awk
提问by jasonmclose
Believe it or not, I can't find the answer to what I would think would be this very basic question.
信不信由你，我找不到这个非常基本的问题的答案。
In awk, how can I loop over the input string character by character? Let's say I just wanted to print them out. Is there an array I can access? Or do I need to use substr?
在 awk 中，如何逐个字符地循环输入字符串？假设我只是想把它们打印出来。有我可以访问的数组吗？或者我需要使用 substr 吗？
Basically, something like:
基本上，类似于：
echo "here is a string" | awk '
{ for(i=0; i<[length of input string]; i++)
printf [value at index i in array x];
}'
Frankly, I'm embarrassed.
老实说，我很尴尬。
回答by Michael J. Barber
You can convert a string to an array using split:
您可以使用split以下方法将字符串转换为数组：
echo "here is a string" | awk '
{
split([jaypal:~/Temp] echo "here is a string" | awk -v FS="" '
{for (i=1;i<=NF;i++) printf "Character "i": " $i"\n"}'
Character 1: h
Character 2: e
Character 3: r
Character 4: e
Character 5:
Character 6: i
Character 7: s
Character 8:
Character 9: a
Character 10:
Character 11: s
Character 12: t
Character 13: r
Character 14: i
Character 15: n
Character 16: g
, chars, "")
for (i=1; i <= length(echo here is a string | awk '{
for (i=0; ++i <= length(awk 'kent$ echo "I am a String"|awk '##代码##=gensub(/(.)/,"\1\n","g")'
I
a
m
a
S
t
r
i
n
g
=gensub(/(.)/,"\1\n","g")' file
);)
printf "%s\n", substr(##代码##, i, 1)
}'
); i++) {
printf("%s\n", chars[i])
}
}'
This prints the characters vertically, one per line.
这将垂直打印字符，每行一个。
回答by jaypal singh
By default in awkthe Field Separator (FS)is spaceor tabs. Since you mentioned you wanted to loop over each character and not word, we will have to redefine the FS to nothing. Something like this -
默认情况下，在awk该Field Separator (FS)ISspace或tabs。由于您提到要遍历每个字符而不是单词，因此我们必须将 FS 重新定义为空。像这样的东西——
回答by Dimitre Radoulov
Not all awk implementations support the above solutions. In that case you could use substr:
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：
##代码##P.S. In some awkimplementations length without arguments defaults to $0, i.e. lengthand length($0)are equivalent.
PS 在一些awk实现中，没有参数的 length 默认为$0，即length和length($0)是等价的。
回答by Kent
if you have gawk:
如果你有目瞪口呆：
##代码##test:
测试：
##代码##