文字ベクトルのRソートルールは何ですか？

Question

Rは、文字ベクトルをASCIIではなくアルファベットとして記述するシーケンスでソートします。例えば

：

sort(c("dog", "Cat", "Dog", "cat")) 
[1] "cat" "Cat" "dog" "Dog" 

3つの質問：

1. このソート順序を記述するための技術的に正しい用語は何ですか？
2. 私はCRANのマニュアルでこれを参照することができません。 Rのソートルールの説明はどこで見つけることができますか？
3. これは、C、Java、Perl、PHPなどの他の言語のこの種の動作とは異なりますか？ sort()状態の

Answer 1

Details:：

The sort order for character vectors will depend on the collating 
sequence of the locale in use: see ‘Comparison’. The sort order 
for factors is the order of their levels (which is particularly 
appropriate for ordered factors). 

とhelp(Comparison)、その後示しています

Comparison of strings in character vectors is lexicographicwithin 
the strings using the collating sequence of the locale in use:see 
‘locales’. The collating sequence of locales such as ‘en_US’ is 
normally different from ‘C’ (which should use ASCII) and can be 
surprising. Beware of making _any_ assumptions about the 
collation order: e.g. in Estonian ‘Z’ comes between ‘S’ and ‘T’, 
and collation is not necessarily character-by-character - in 
Danish ‘aa’ sorts as a single letter, after ‘z’. In Welsh ‘ng’ 
may or may not be a single sorting unit: if it is it follows ‘g’. 
Some platforms may not respect the locale and always sort in 
numerical order of the bytes in an 8-bit locale, or in Unicode 
point order for a UTF-8 locale (and may not sort in the same order 
for the same language in different character sets). Collation of 
non-letters (spaces, punctuation signs, hyphens, fractions and so 
on) is even more problematic. 

をので、それはあなたのロケール設定によって異なります。