计算Python字符串中字母出现次数

Question

所以我得到了一个DNA序列。

ACCAGAGCGGCACAGCAGCGACATCAGCACTAGCACTAGCATCAGCATCAGCATCAGC
CTACATCATCACAGCAGCATCAGCATCGACATCAGCATCAGCATCAGCATCGACGACT
ACACCCCCCCCGGTGTGTGTGGGGGGTTAAAAATGATGAGTGATGAGTGAGTTGTGTG
CTACATCATCACAGCAGCATCAGCATCGACATCAGCATCAGCATCAGCATCGACGACT
TTCTATCATCATTCGGCGGGGGGATATATTATAGCGCGCGATTATTGCGCAGTCTACG
TCATCGACTACGATCAGCATCAGCATCAGCATCAGCATCGACTAGCATCAGCTACGAC

我需要计算基数。

同样由于某种原因，它有时可以在同一个字符串中以大写或小写之间交替。

Answer 1

for base in 'ACGT':
  print base, thesequence.count(base) + thesequence.count(base.lower())