解析Python中的字符串3

Question

我有以下变量。是否有办法挑出“Al＃ex”并将其分配给新变量

string="@Al#ex$" 
firstChar="A" 
lastChar="x" 

结果应该是这样的。

print(finalString) 
>"Al#ex" 

在此先感谢。

Answer 1

使用str.find/str.rfind：

def pick1(string, first, last): 
    i = string.find(first) 
    if i < 0: return '' 
    j = string.find(last, i+1) 
    if j < 0: return '' 
    return string[i:j+1] 

def pick2(string, first, last): 
    i = string.find(first) 
    if i < 0: return '' 
    j = string.rfind(last, i+1) 
    if j < 0: return '' 
    return string[i:j+1] 

---

>>> pick1('@Al#ex$', 'A', 'x') 
'Al#ex' 
>>> pick2('@Al#ex$', 'A', 'x') 
'Al#ex' 
>>> 
>>> pick1('@xl#eA$', 'A', 'x') 
'' 
>>> pick2('@xl#eA$', 'A', 'x') 
'' 
>>> 
>>> pick1('x@Al#ex$', 'A', 'x') 
'Al#ex' 
>>> pick2('x@Al#ex$', 'A', 'x') 
'Al#ex' 
>>> 
>>> pick1('x@Al#ex$x', 'A', 'x') 
'Al#ex' 
>>> pick2('x@Al#ex$x', 'A', 'x') 
'Al#ex$x' 

Answer 2

mystring="@Al#ex$" 
firstChar="A" 
lastChar="x" 
finalString = mystring[mystring.index(firstChar):mystring.rindex(lastChar)+1] 
print (finalString) 

输出

Al#ex