Perl教学第十篇格式化输出之二

时间： 2021-07-31 作者：daque

三、在打字与印刷方法中表露值咱们运用打字与印刷方法的重要因为固然是方法化存贮在大略变量或数组变量中的值进而天生可读性好的输入，这一手段用“定义域”来实行。每个定义域指定一个值，如变量或表白式，挪用write因变量时，该值就以定义域指定的方法表露。1、通用的打字与印刷方法打字与印刷方法的一个缺陷是设置中包括了变量名，比方：format myformat ===========================================================the winning number is @<<<<< $winnum==========================================================. 当挪用write输入此方法时，必需记着它运用了变量$winnum。用子步调平局域变量就不妨创造更通用的打字与印刷方法。下例从stdin输出一个文献并输入五个展示频次最高的假名及展示度数。1 : #!/usr/local/bin/perl2 : 3 : while ($line = ) {4 : $line =~ tr/a-z/a-z/;5 : $line =~ s/[^a-z]//g;6 : @letters = split(//, $line);7 : foreach $letter (@letters) {8 : $lettercount{$letter} += 1;9 : }10: }11: 12: $~ = "writeheader";13: write;14: $count = 0;15: foreach $letter (reverse sort occurrences16: (keys(%lettercount))) {17: &write_letter($letter, $lettercount{$letter});18: last if (++$count == 5);19: }20: 21: sub occurrences {22: $lettercount{$a} <=> $lettercount{$b};23: }24: sub write_letter {25: local($letter, $value) = @_;26: 27: $~ = "writeletter";28: write;29: }30: format writeheader =31: the five most frequently occurring letters are:32: .33: format writeletter =34: @: @<<<<<<35: $letter, $value36: . 运转截止如次：$ programthis is a test file.this test file contains some input.the quick brown fox jumped over the lazy dog.^dthe five most frequently occurring letters are:t: 10e: 9i: 8s: 7o: 6$

Perl教学第十篇格式化输出之二

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Perl教学 第十篇 格式化输出之二

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Perl教学第十篇格式化输出之二