bash bash中字符串的长度

Length of string in bash

提问by AJP

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

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？

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

How do you set another variable to the output 11?

你如何为输出设置另一个变量11？

采纳答案by F. Hauri

UTF-8 string length

UTF-8 字符串长度

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

除了fedorqui的正确答案之外，我还想说明字符串长度和字节长度之间的区别：

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.\n" "${myvar}" $chrlen $bytlen

will render:

将呈现：

Généralités is 11 char len, but 14 bytes len.

you could even have a look at stored chars:

你甚至可以看看存储的字符：

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=$oLcAll
printf "%s has %d chars, %d bytes: (%s).\n" "${myvar}" $chrlen $bytlen "$myreal"

will answer:

会回答：

Généralités has 11 chars, 14 bytes: ($'G31n31ralit31s').

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

注意：根据Isabell Cowan 的评论，我已经将设置$LC_ALL与$LANG.

Length of an argument

参数的长度

Argument work same as regular variables

参数工作与常规变量相同

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

will work as

将作为

strLen théorème
String 'théorème' is 10 bytes, but 8 chars len: $'th31or30me'

Useful printfcorrection tool:

有用的printf校正工具：

If you:

如果你：

for string in Généralités Language Théorème Février  "Left: ←" "Yin Yang ?";do
    printf " - %-14s is %2d char length\n" "'$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

Not really pretty... For this, there is a little function:

不是很漂亮......为此，有一个小功能：

strU8DiffLen () { 
    local bytlen oLang=$LANG oLcAll=$LC_ALL
    LANG=C LC_ALL=C
    bytlen=${#1}
    LANG=$oLang LC_ALL=$oLcAll
    return $(( bytlen - ${#1} ))
}

Then now:

那么现在：

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

Unfortunely, this is not perfect!

不幸的是，这并不完美！

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...

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、反向置换和其他不可能那么简单的行为......

Have a look at diffU8test.shor diffU8test.sh.txtfor more limitations.

查看diffU8test.sh或diffU8test.sh.txt了解更多限制。

回答by fedorqui 'SO stop harming'

To get the length of a string stored in a variable, say:

要获取存储在变量中的字符串的长度，请说：

myvar="some string"
size=${#myvar} 

To confirm it was properly saved, echoit:

为了确认它被正确保存，echo它：

$ echo "$size"
11

回答by atesin

You can use:

您可以使用：

MYSTRING="abc123"
MYLENGTH=$(printf "%s" "$MYSTRING" | wc -c)

• wc -cor wc --bytesfor byte counts = Unicode characters are counted with 2, 3 or more bytes.
• wc -mor wc --charsfor character counts = Unicode characters are counted single until they use more bytes.

• wc -c或wc --bytes对于字节计数 = Unicode 字符按 2、3 或更多字节计数。
• wc -m或者wc --chars对于字符计数 = Unicode 字符被计算为单个，直到它们使用更多字节。

回答by dmatej

I wanted the simplest case, finally this is a result:

我想要最简单的情况，最后这是一个结果：

echo -n 'Tell me the length of this sentence.' | wc -m;
36

回答by Dick Guertin

If you want to use this with command line or function arguments, make sure you use size=${#1}instead of size=${#$1}. The second one may be more instinctual but is incorrect syntax.

如果您想将其与命令行或函数参数一起使用，请确保使用size=${#1}代替size=${#$1}。第二个可能更本能，但语法不正确。

回答by JGFMK

In response to the post starting:

回复帖子开始：

If you want to use this with command line or function arguments...

如果您想将其与命令行或函数参数一起使用...

with the code:

使用代码：

size=${#1}

There might be the case where you just want to check for a zero length argument and have no need to store a variable. I believe you can use this sort of syntax:

可能存在您只想检查零长度参数而无需存储变量的情况。我相信你可以使用这种语法：

if [ -z "" ]; then
    #zero length argument 
else
    #non-zero length
fi

See GNUand wooledgefor a more complete list of Bash conditional expressions.

有关Bash 条件表达式的更完整列表，请参阅GNU和woodedge。

回答by thistleknot

Using your example provided

使用您提供的示例

#KISS (Keep it simple stupid)
size=${#myvar}
echo $size

回答by Mukesh Shakya

Here is couple of ways to calculate length of variable :

这里有几种计算变量长度的方法：

echo ${#VAR}
echo -n $VAR | wc -m
echo -n $VAR | wc -c
printf $VAR | wc -m
expr length $VAR
expr $VAR : '.*'

and to set the result in another variable just assign above command with back quote into another variable as following:

并将结果设置在另一个变量中，只需将带有反引号的上述命令分配给另一个变量，如下所示：

otherVar=`echo -n $VAR | wc -m`   
echo $otherVar

http://techopsbook.blogspot.in/2017/09/how-to-find-length-of-string-variable.html

http://techopsbook.blogspot.in/2017/09/how-to-find-length-of-string-variable.html