R tm封装/qdap输出中出现特殊字符

我试图使用以下数据集在R中创建一个术语文档矩阵

  EmailSubject
Buy the stunning new phone
The game changer is here.
Experience a phone ahead of its time.
Thank You Chennai
Limited Period offer
Valentines day special
Buy a phone at 10000 and get a new sim free
Limited Period offer
Valentines day special
Buy a phone at 10000 and get a new sim free
Buy the stunning new phone
The game changer is here.
Experience a phone ahead of its time.
Thank You Chennai
Limited Period offer
Valentines day special
Buy a phone at 10000 and get a new sim free
Thank You Chennai
Limited Period offer
 Valentines day special
 Buy a phone at 10000 and get a new sim free
Buy a phone at 10000 and get a new sim free
Buy the stunning new phone
The game changer is here.

提前体验手机。 谢谢你，钦奈 限时要约

我使用了qdap和freq_术语。以下是预期的输出

  freq_terms(DF)


     Expected Output    Frequency
      Buy               4
      Get               5
       a                7
      thank             12
     Stunning            6
         The             7
         New             10
       Valentines        4
        phone            7

以下特殊字符经常出现，导致数据不合适

           valentinea€™s, a€™s instead of valentines, as. I have tried the same with tm package also. 

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我用gsub替换了这些字符，但效果不是很好。有人能建议一种方法吗？

听起来像是编码问题。问题听起来像编码问题