对于某些字符串，需要输入为特定的格式，通过sprintf可以很方便的完成，不需要专门进行其他处理。
perl中的sprintf的用法如下：
sprintf FORMAT,LIST
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比如：
$result = sprintf("%08d",$number);让$number有8个前导零。
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$rounded = sprintf("%.3f",$number);
让小数点后有3位数字。
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sprintf允许的如下常用的转换：
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%%???????? 百分号
%c?????????? 把给定的数字转化为字符
%s?????????? 字符串
%d???????????带符号整数，十进制
%u??????? ?? 无符号整数，十进制
%o ? ? ? ? ? 无符号整数，八进制
%x ? ? ? ? ? 无符号整数，十六进制
%e?????????? 浮点数，科学计算法
%f??????????? 浮点数，用于固定十进制计数
%g?????????? 浮点数，包括%e和%f
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?%X?? like %x,but using upper-case letters
?%E?? like %e,but using an upper-case "E"
?%G?? like %g,but with an upper-case "E" (if applicable)
?%b?? an unsigned integer,in binary
?%B?? like %b,but using an upper-case "B" with the # flag
?%p?? a pointer (outputs the Perl value's address in hexadecimal)
?%n?? special: *stores* the number of characters output so far
????? into the next variable in the parameter list
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通过$1,$2等可以改变顺序：
?printf '%2$d %1$d',12,34;????? # prints "34 12"
?printf '%3$d %d %1$d',1,2,3;? # prints "3 1 1"
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printf '<% d>',? 12;?? # prints "< 12>"
printf '<%+d>',? 12;?? # prints "<+12>"
printf '<%6s>',? 12;?? # prints "<??? 12>"
printf '<%-6s>',12;?? # prints "<12??? >"
printf '<%06s>',12;?? # prints "<000012>"
printf '<%#o>',? 12;?? # prints "<014>"
printf '<%#x>',? 12;?? # prints "<0xc>"
printf '<%#X>',? 12;?? # prints "<0XC>"
printf '<%#b>',? 12;?? # prints "<0b1100>"
printf '<%#B>',? 12;?? # prints "<0B1100>"
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?printf '<%f>',1;??? # prints "<1.000000>"
?printf '<%.1f>',1;? # prints "<1.0>"
?printf '<%.0f>',1;? # prints "<1>"
?printf '<%e>',10;?? # prints "<1.000000e+01>"
?printf '<%.1e>',10; # prints "<1.0e+01>"
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printf '<%.6d>',1;????? # prints "<000001>"
printf '<%+.6d>',1;???? # prints "<+000001>"
printf '<%-10.6d>',1;?? # prints "<000001??? >"
printf '<%10.6d>',1;??? # prints "<??? 000001>"
printf '<%010.6d>',1;?? # prints "<??? 000001>"
printf '<%+10.6d>',1;?? # prints "<?? +000001>"
printf '<%.6x>',1;????? # prints "<000001>"
printf '<%#.6x>',1;???? # prints "<0x000001>"
printf '<%-10.6x>',1;?? # prints "<000001??? >"
printf '<%10.6x>',1;??? # prints "<??? 000001>"
printf '<%010.6x>',1;?? # prints "<??? 000001>"
printf '<%#10.6x>',1;?? # prints "<? 0x000001>"
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printf '<%.5s>',"truncated";?? # prints "<trunc>"
printf '<%10.5s>',"truncated"; # prints "<???? trunc>"
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???????????? printf "%2/$d %d/n",??? 12,34;?????????????? # will print "34
"
???????????? printf "%2/$d %d %d/n",34;?????????????? # will print "34
4/n"
???????????? printf "%3/$d %d %d/n",34,56;?????????? # will print "56
4/n"
???????????? printf "%2/$*3/$d %d/n",3;?????????? # will print " 3
n"
转自:?http://www.voidcn.com/article/p-mnevzamp-q.html
