python - 对字符向量进行排序时的不同结果

Question

我想知道在对字符向量进行排序时，R 排序算法是如何工作的

a = c("aa(150)", "aa(1)S")
sort(a)
# [1] "aa(150)" "aa(1)S" 
a = c("aa(150)", "aa(1)")
sort(a)
# [1] "aa(1)" "aa(150)"

R不是从左到右逐一比较字符的整数值吗？为什么添加一个字符可以改变结果？

我以为排序是由“5”和“)”字符决定的，后面的字符被忽略。

与Python比较

In [1]: a=["aa(150)","aa(1)"]
In [2]: sorted(a)
Out[2]: ['aa(1)', 'aa(150)']
In [3]: a=["aa(150)","aa(1)S"]
In [4]: sorted(a)
Out[4]: ['aa(1)S', 'aa(150)']

Answer 1

将语言环境设置为默认值，这将在大多数情况下关闭特定于语言环境的排序:

Sys.setlocale("LC_COLLATE", "C")
a=c("aa(150)","aa(1)S")
sort(a)
#[1] "aa(1)S"  "aa(150)"

---

由于语言差异，字符串排序必须是国际特定的。来自 ?sort 的帮助:

The sort order for character vectors will depend on the collating sequence of the locale in use: see Comparison.

然后我们可以转到 ?Comparisons 以获得:

Comparison of strings in character vectors is lexicographic within 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.

如前所述，由于每种语言使用字母的方式不同，因此区域设置对于排序很重要。