Usage of TR in Perl (reproduced)

Reprint: http://blog.sina.com.cn/s/blog_4a0824490101hncz.html

(1)/C means to replace the characters that are not matched.

$temp = "Aaaabcdef";

$count = $temp =~tr/a/h/c;

Print "$temp \t$count\n";

Results: Aaaahhhhh 5

(2)/d: Replace all characters on the match

$temp = "Aaaabcdef";

$count = $temp =~tr/a/h/d;

Print "$temp \t$count\n";

Results: Hhhhbcdef 4

(3)/s: Indicates that if there are multiple consecutive characters in the character to be replaced, the redundancy is redundant:

$temp = "Aaaabcdef";

$count = $temp =~tr/a/h/ds;

Print "$temp \t$count\n";

Results: Hbcdef 4

$temp = "Aaaabcdef";

$count = $temp =~tr/a/h/cs;

Print "$temp \t$count\n";

Results: Aaaah 5

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Also, let me summarize the usefulness of tr:

$count = $temp =~tr/a//; The number of a in the #表示计算 $temp, $temp does not change the value

$count = $temp =~tr/a/a/; #表示计算 the number of a in the $temp, $temp does not change the value and the meaning above

$temp = "Aaaabcdef";

$count = $temp =~tr/[a-z]/[a-z]/; #表示进行大小写转换

Print "$temp \t$count\n";

results: Aaaabcdef9 if written as $count= $temp =~tr/[a-z]/[a-z]/, then $temp will not change, only the number of capital letters in the $temp is counted . results: AAAABCDEF9

Usage of TR in Perl (reproduced)