替換python字符串/列表中的索引列表中的字符

Question

我有以下字典：

s_dict = {'s' : 'ATGCGTGACGTGA'}

我想將存儲在位置4、6、7和10處的鍵's'的字典值存儲的字符串更改為h，k，p和r。

pos_change = {'s' : ['4_h', '6_k', '7_p', '10_r']}

我可以考慮的方式是循環的：

for key in s_dict:
    for position in pos_change[key]:
        pos = int(position.split("_")[0])
        char = position.split("_")[1]
        l = list(s_dict[key])
        l[pos]= char
        s_dict[key] = "".join(l)

輸出：

s_dict = {'s': 'ATGChTkpCGrGA'}

這可以正常工作，但我的實際s_dict文件約為1.5 Gb。 有沒有一種更快的方法來替換字符串或列表中特定索引處的字符列表？

謝謝！

Answer 1

作為解決方案的一種選擇，您可以使用s_dict['s'] = '%s%s%s' % (s_dict['s'][:pos], char, s_dict['s'][pos+1:])而不是列出並加入

In [1]: s_dict = {'s' : 'ATGCGTGACGTGA' * 10}
   ...: pos_change = {'s' : ['4_h', '6_k', '7_p', '10_r']}
   ...: 
   ...: def list_join():
   ...:     for key in s_dict:
   ...:         for position in pos_change[key]:
   ...:             pos = int(position.split("_")[0])
   ...:             char = position.split("_")[1]
   ...:             l = list(s_dict[key])
   ...:             l[pos]= char
   ...:             s_dict[key] = "".join(l)
   ...: 
   ...: def by_str():
   ...:     for key in s_dict:
   ...:         for position in pos_change[key]:
   ...:             pos = int(position.split("_")[0])
   ...:             char = position.split("_")[1]
   ...:             values = s_dict['s'][:pos], char, s_dict['s'][pos+1:]
   ...:             s_dict['s'] = '%s%s%s' % values
   ...:             

In [2]: %timeit list_join()
11.7 µs ± 191 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

In [3]: %timeit by_str()
4.29 µs ± 46.7 ns per loop (mean ± std. dev. of 7 runs, 100000 loops each)

Answer 2

這是我對您有趣的問題的看法：

s_dict = {'s' : 'ATGCGTGACGTGA'}    
pos_change = {'s' : ['4_h', '6_k', '7_p', '10_r']}

---

# 1rst change `pos_change` into something more easily usable
pos_change = {k: dict(x.split('_') for x in v) for k, v in pos_change.items()}
print(pos_change)  # {'s': {'4': 'h', '6': 'k', '7': 'p', '10': 'r'}}

---

# and then... 
for k, v in pos_change.items():
  temp = set(map(int, v))
  s_dict[k] = ''.join([x if i not in temp else pos_change[k][str(i)] for i, x in enumerate(s_dict[k])])

print(s_dict)  # {'s': 'ATGChTkpCGrGA'}