bash中字符串的长度 [英] Length of string in bash

问题描述

如何获取存储在变量中的字符串的长度并将其分配给另一个变量?

How do you get the length of a string stored in a variable and assign that to another variable?

myvar="some string"
echo ${#myvar}  
# 11

如何为输出11设置另一个变量?

How do you set another variable to the output 11?

推荐答案

UTF-8 字符串长度

除了fedorqui 的正确答案，我还想展示string 长度和字节长度:

UTF-8 string length

In addition to fedorqui's correct answer, I would like to show the difference between string length and byte length:

myvar='Généralités'
chrlen=${#myvar}
oLang=$LANG oLcAll=$LC_ALL
LANG=C LC_ALL=C
bytlen=${#myvar}
LANG=$oLang LC_ALL=$oLcAll
printf "%s is %d char len, but %d bytes len.
" "${myvar}" $chrlen $bytlen

将呈现:

Généralités is 11 char len, but 14 bytes len.

您甚至可以查看存储的字符:

you could even have a look at stored chars:

myvar='Généralités'
chrlen=${#myvar}
oLang=$LANG oLcAll=$LC_ALL
LANG=C LC_ALL=C
bytlen=${#myvar}
printf -v myreal "%q" "$myvar"
LANG=$oLang LC_ALL=$oLcAll
printf "%s has %d chars, %d bytes: (%s).
" "${myvar}" $chrlen $bytlen "$myreal"

会回答:

Généralités has 11 chars, 14 bytes: ($'G303251n303251ralit303251s').

注意:根据 Isabell Cowan 的评论，我已经将设置添加到 $LC_ALL 和 $LANG.

Nota: According to Isabell Cowan's comment, I've added setting to $LC_ALL along with $LANG.

参数与常规变量相同

showStrLen() {
    local bytlen sreal oLang=$LANG oLcAll=$LC_ALL
    LANG=C LC_ALL=C
    bytlen=${#1}
    printf -v sreal %q "$1"
    LANG=$oLang LC_ALL=$oLcAll
    printf "String '%s' is %d bytes, but %d chars len: %s.
" "$1" $bytlen ${#1} "$sreal"
}

将作为

showStrLen théorème
String 'théorème' is 10 bytes, but 8 chars len: $'th303251or303250me'

好用的printf修正工具:

如果你:

Useful printf correction tool:

If you:

for string in Généralités Language Théorème Février  "Left: ←" "Yin Yang ☯";do
    printf " - %-14s is %2d char length
" "'$string'"  ${#string}
done

 - 'Généralités' is 11 char length
 - 'Language'     is  8 char length
 - 'Théorème'   is  8 char length
 - 'Février'     is  7 char length
 - 'Left: ←'    is  7 char length
 - 'Yin Yang ☯' is 10 char length

不是很漂亮的输出！

为此，这里有一个小功能:

For this, here is a little function:

strU8DiffLen() {
    local charlen=${#1} LANG=C LC_ALL=C
    return $(( ${#1} - charlen ))
}

或写成一行:

strU8DiffLen() { local chLen=${#1} LANG=C LC_ALL=C;return $((${#1}-chLen));}

那么现在:

for string in Généralités Language Théorème Février  "Left: ←" "Yin Yang ☯";do
    strU8DiffLen "$string"
    printf " - %-$((14+$?))s is %2d chars length, but uses %2d bytes
" 
        "'$string'" ${#string} $((${#string}+$?))
  done 

 - 'Généralités'  is 11 chars length, but uses 14 bytes
 - 'Language'     is  8 chars length, but uses  8 bytes
 - 'Théorème'     is  8 chars length, but uses 10 bytes
 - 'Février'      is  7 chars length, but uses  8 bytes
 - 'Left: ←'      is  7 chars length, but uses  9 bytes
 - 'Yin Yang ☯'   is 10 chars length, but uses 12 bytes

不幸的是，这并不完美！

但是留下了一些奇怪的 UTF-8 行为，比如双倍行距字符、零行距字符、反向置换和其他不那么简单的......

Unfortunely, this is not perfect!

But there left some strange UTF-8 behaviour, like double-spaced chars, zero spaced chars, reverse deplacement and other that could not be as simple...

看看 diffU8test.sh 或 diffU8test.sh.txt 了解更多限制.

Have a look at diffU8test.sh or diffU8test.sh.txt for more limitations.

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