哈希有額外的按鍵

這是我哈希有額外的按鍵

my %count_words; 

while (<DATA>){ 
    my $line= $_; 
    chomp $line; 
    my @words = split (/ /, "$line"); 
    foreach my $word(@words){ 
     $count_words{"$word"}++; 
    } 
} 

foreach my $key (%count_words){ 
    print "\"$key\" occurs \"$count_words{$key}\" times\n"; 
} 

__DATA__ 
we name is something 
this is what it does 
we food food food food

，這是輸出我得到

"it" occurs "1" times 
"1" occurs "" times 
"what" occurs "1" times 
"1" occurs "" times 
"name" occurs "1" times 
"1" occurs "" times 
"food" occurs "1" times 
"1" occurs "" times 
"does" occurs "1" times 
"1" occurs "" times 
"is" occurs "2" times 
"2" occurs "" times 
"we" occurs "2" times 
"2" occurs "" times 
"food" occurs "3" times 
"3" occurs "" times 
"something" occurs "1" times 
"1" occurs "" times 
"this" occurs "1" times 
"1" occurs "" times

我的問題是，爲什麼在那裏創建了這些附加的密鑰，其本質上是先前創建的鍵 - >值對的值。

這是我所期待

"it" occurs "1" times 
"what" occurs "1" times 
"name" occurs "1" times 
"food" occurs "1" times 
"does" occurs "1" times 
"is" occurs "2" times 
"we" occurs "2" times 
"food" occurs "3" times 
"something" occurs "1" times 
"this" occurs "1" times

可有人請糾正我的明顯錯誤？

來源

2012-12-10 Amey

你的錯誤是在你的foreach循環，你需要的keys功能：

foreach my $key (keys %count_words){ 
    print "\"$key\" occurs \"$count_words{$key}\" times\n"; 
}

，否則，你的foreach通過所有鍵和值迭代。

來源

2012-12-10 16:35:28

D'oh！十秒鐘太慢....：P – 2012-12-10 16:37:33

那麼誰會想到:)謝謝 – Amey

嘗試：

foreach my $key (keys %count_words){ 
    print "\"$key\" occurs \"$count_words{$key}\" times\n"; 
}

的問題是，當您通過遍歷一個哈希表，您交替通過按鍵和值迭代。

來源

2012-12-10 16:36:24

'print qq（「$ key occurrence」$ count_words {$ key}「times」\ n）;' – TLP

的問題是，你不使用

use strict; 
use warnings;

如果有，那就給你一個線索，錯誤在你的代碼

Use of uninitialized value $count_words{"1"}...

或者其他類似的效果。

問題是，正如Tim A已經指出的那樣，您在列表上下文中使用了散列，這意味着它擴展爲鍵和值。您應該像他所建議的那樣使用keys函數。

來源

2012-12-10 16:38:51 TLP

哈希有額外的按鍵

回答

相關問題