Question

''''函数是一种有效且并行化的方法，用于在长字符向量字符串中查找字符。有没有函数或简单的方法在python中实现它？

Answer 1

如果这些元素满足某个条件，则获取可枚举集合中元素索引的pythonic方法是使用list comprehension和enumerate()。例如，要查找列表中奇数元素的所有索引：

>>> mylist = [1,2,3,4,5,6,7,8]
>>> [index for index, item in enumerate(mylist) if item%2]
[0, 2, 4, 6]

Answer 2

我不太确定R是如何工作的，但这里有一些想法让你开始

lookingFor = 'a'
print "the string of all '%s's is" %lookingFor, ''.join(char for char in myLongString if char==lookingFor)
print "there are %s many instances of the character '%s' in the string '%s'" %(myLongString.count(lookingFor), lookingFor, myLongString)
import collections
print "there are %s many instances of the character '%s' in the string '%s'" %(collections.Counter(myLongString)[lookingFor], lookingFor, myLongString)

Answer 3

或包装成通用函数：

PHP Fatal error:  Uncaught Google_Service_Exception: {
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "notFound",
    "message": "Not Found"
   }
  ],
  "code": 404,
  "message": "Not Found"
 }
}

e.g：

>>> which = lambda targetList, f: [index for index, item in enumerate(targetList) if f(item)]

在python中有与R的“哪个”功能类似的功能吗？

3 个答案: