Python取子字符串方法

要求：从字符串中

sfsfsd345#-3sfsfsd3.4me

345#-3出来

Python自定义函数的写法如下所示:

>>> ================================ RESTART ================================
>>> def getsubstr(txt_s):
        #处理换行符问题
        t=txt_s
        findex=txt_s.find('#')
        s_len=len(txt_s)
        t=t[0:findex]
        dkbh=''
        bh_s=''
        for a in t:
                 #获取是数字 中划线 下划线的子字符串
                 if(a.isdigit()==True or a=='-' or a=='_'):
                     if(dkbh==''):
                          dkbh=a
                     else:
                          dkbh+=a
        s=txt_s[findex+1:findex+2]
        if(s=='-'):            
            s=txt_s[findex+1:s_len]            
            for b in s:
                if(b.isdigit()==True or b=='-' or b=='_'):
                     if(bh_s==''):
                           bh_s=b
                     else:
                           bh_s+=b
                else:
                     break
        dkbh+='#'+bh_s         
        return dkbh 

>>> print getsubstr('sfsfsd345#-3sfsfsd3.4men')
345#-3
>>> 

>>> ================================ RESTART ================================
>>> def getAreaVal(txt_s):    
    findex=txt_s.find('#')
    s_len=len(txt_s)    
    rb=''
    bh_s=''
    s=txt_s[findex+1:findex+2]
    if(s=='-'):            
          s=txt_s[findex+1:s_len]            
          for b in s:
                if(b.isdigit()==True or b=='-' or b=='_'):
                     if(bh_s==''):
                           bh_s=b
                     else:
                           bh_s+=b
                else:
                     break
    q=txt_s[findex+1:s_len]
    for c in q:
        if(c.isdigit()==True or c=='-' or c=='_' or c=='.'):
            if(rb==''):
                rb=c
            else:
                rb+=c
        else:
            continue
    return rb.replace(bh_s,'')

>>> print getAreaVal('sfsdfd45#-2sfdfs45.6men')
45.6
>>>