---
tags: python
---

運用Python解生物資訊問題(3)
===
## 練習1
先下載herpesvirus_genome.json
[herpesvirus_genome.json](https://muddle2.cs.huji.ac.il/ru19/course/view.php?id=68&section=3)

### A)
Find the frequency of each amino-acid in the herpesvirus's proteome.
找出herpesvirus的蛋白質體中，所有胺基酸出現的頻率。

import os
import json
from collections import Counter
# r代表raw python string literal, 不用正規表達式表示。
DIR = r'C://downloads'

f = open(os.path.join(DIR, 'herpesvirus.json'), 'r')

data = json.load(f)

f.close()

# 將計算好的氨基酸出現次數除以總胺基酸數
def normalize(counter):
    total = sum(counter.values())
    return {key: count / total for key, count in counter.items()}

# 建立空的記數字典
all_aa_counter = Counter()
# 這邊可以先另外用Notepad++開herpesvirus.json檔案看
# coding regions以list儲存每個coding region資訊
# 其中每個coding region有個key值為translation
# 當中儲存該coding region的胺基酸序列
for coding_region in data['coding_regions']:
   # 用update字典的方法加入計數器 
   aa_aa_counter.update(coding_region['translation']
)

aa_all_freq = normalize(all_aa_counter)
print(all_aa_freq)