string 将整数作为字符串添加到变量 bash
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Add integers as strings to a variable bash
提问by Matt R
I want to output a string by adding random integer to a variable to create the string. Bash however, just adds the numbers together.
我想通过将随机整数添加到变量来创建字符串来输出字符串。然而，Bash 只是将数字相加。
#!/bin/bash
b=""
for ((x=1; x<=3; x++))
do
number=$RANDOM
let number%=9
let b+=$number
done
echo ${b}
Say every random number is 1, the script will output 3 instead of 111. How do I achieve the desired result of 111?
假设每个随机数为 1，脚本将输出 3 而不是 111。如何达到 111 的预期结果？
回答by Lekensteyn
There are several possibilities to achieve your desired behavior. Let's first examine what you've done:
有几种可能性可以实现您想要的行为。让我们首先检查你做了什么：
let b+=$number
Running help let:
运行help let：
let: let ARGUMENT...
Evaluate arithmetic expressions.
That explains why let b+=$numberperforms an integer addition (1, 2, 3) of $numberto binstead of string concatenation.
这解释了为什么let b+=$number执行to的整数加法 ( 1, 2, 3)而不是字符串连接。$numberb
Simply remove letand the desired behavior 1, 11, 111will occur.
只需删除，就会发生let所需的行为1, 。11111
The other method to perform string concatenation:
执行字符串连接的另一种方法：
b="$b$number"
Yes, simply "let bbecome the result of concatenating band number.
是的，只需“让b成为连接b和的结果number。
As a side note, b=""is equivalent to b=as ""is expanded to an empty string. Module operation on a variable can be done with arithmetic expansion: number=$((RANDOM%9)).
作为旁注，b=""相当于b=as""被扩展为一个空字符串。变量的模块运算可以通过算术展开来完成：number=$((RANDOM%9)).
