用re.sub替換正則表達式的一部分

Question

我想只替換傳入re.sub的正則表達式的部分（[^\d+]只是爲了確保在此之後沒有數字，即整個整數（全部數字）被捕獲）。但是，下面的代碼會替換下一個字符（即在第一個示例中吞嚥下一個「」）。

import re 
pattern = r'foo-%d[^\d+]' 

k = 12 # only substitute entire "foo-12" occurrences 
result = re.sub(pattern % k, '@foo-%d@' % k, 'dasds foo-12 gfd9843') 
# got: result == 'dasds @foo-12@gfd9843' 
assert result == 'dasds @foo-12@ gfd9843', result 

k = 1 # only substitute entire "foo-1" occurrences 
result = re.sub(pattern % k, '@foo-%d@' % k, 'dasds foo-12 gfd9843') 
assert result == 'dasds foo-12 gfd9843', result 

k = 1 # only substitute entire "foo-1" occurrences 
result = re.sub(pattern % k, '@foo-%d@' % k, 'dasds foo-11 gfd9843') 
assert result == 'dasds foo-11 gfd9843', result 

我該如何解決這個問題？我是否至少在正則表達式的正確軌道上？

Answer 1

使用\b這裏

import re 
k = 12 # only substitute entire "foo-12" occurrences 
s = 'dasds foo-12 gfd9843' 
result = re.sub(r'foo-%d\b' % k, '@foo-%d@' % k, s) 

# got: result == 'dasds @foo-12@gfd9843' 
assert result == 'dasds @foo-12@ gfd9843', result 


k = 1 # only substitute entire "foo-1" occurrences 
result = re.sub(r'foo-%d\b' % k, '@foo-%d@' % k, s) 
assert result == 'dasds foo-12 gfd9843', result