基于python实现判断字符串是否数字算法

 #encoding=utf-8
def is_number(s):
  if s.count(".")==1:  #小数的判断
    if s[0]=="-":
      s=s[1:]
    if s[0]==".":
      return False
    s=s.replace(".","")
    for i in s:
      if i not in "0123456789":
        return False
    else:        #这个else与for对应的
      return True
  elif s.count(".")==0:  #整数的判断
    if s[0]=="-":
      s=s[1:]
    for i in s:
      if i not in "0123456789":
        return False
    else:
      return True
  else:
    return False
print(is_number("1334345345"))
print(is_number("1.12344565"))
print(is_number("-14344343"))
print(is_number("-1.123456"))
print("**********************")
print(is_number("abc"))
print(is_number("1.32.2"))
print(is_number(".2344"))
print(is_number("1234a"))
print(is_number("--1.1"))
print(is_number("--1abc"))

#encoding=utf-8
def is_number(s):
  if s[0]=="-" or s[0] in "0123456789":
    if s.count(".")<=1 and s.count("-")<=1:
      s=s.replace("-","").replace(".","")
      #print (s)
      for i in s:
        if i not in "0123456789":
          return False
      else:        #这个else与for对应
        return True
    else:
      return False 
  else:
    return False
print(is_number("1334345345"))
print(is_number("1.12344565"))
print(is_number("-14344343"))
print(is_number("-1.123456"))
print("**********************")
print(is_number("abc"))
print(is_number("1.32.2"))
print(is_number(".2344"))
print(is_number("1234a"))
print(is_number("--1.1"))
print(is_number("--1abc"))