python变量不能以数字打头详解

Python  /  管理员 发布于 7年前   263

在编写python函数时，无意中发现一个问题：python中的变量不能以数字打头，以下函数中定义了一个变量3_num_varchar，执行时报错。

函数如下：

def database_feild_varchar_trans(in_feild):  '''  transfer the feild if varchar then 3times lang else no transfer  '''  feild_split = in_feild.split(' ')  is_varchar = feild_split[1].find('VARCHAR')  if is_varchar >= 0 :    num_varchar = feild_split[1].replace('VARCHAR','').replace('(','').replace(')','')     print (num_varchar)    3_num_varchar = num_varchar*3    feild_split[1] = feild_split[1].replace(str(num_varchar),str(3_num_varchar))    return feild_split  else:    print ('The feild type is not varchar')    return feild_split

报错信息如下：

>>> runfile('E:/procedure/python/projects/others/table_test.py', wdir='E:/procedure/python/projects/others')Traceback (most recent call last): File "<stdin>", line 1, in <module> File "D:\Python33\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 699, in runfile  execfile(filename, namespace) File "D:\Python33\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 88, in execfile  exec(compile(open(filename, 'rb').read(), filename, 'exec'), namespace) File "E:/procedure/python/projects/others/table_test.py", line 20  3_num_varchar = int(num_varchar)*3        ^SyntaxError: invalid syntax将变量3_num_varchar改为num_varchar_3，运行成功，程序改为如下：import osimport sysstr1='aaa varchar(10)'def database_feild_varchar_trans(in_feild):  '''  transfer the feild if varchar then 3times lang else no transfer  '''  feild_split = in_feild.split(' ')  is_varchar = feild_split[1].find('VARCHAR')  if is_varchar >= 0 :    num_varchar = feild_split[1].replace('VARCHAR','').replace('(','').replace(')','')     print (num_varchar)    num_varchar_3 = num_varchar*3    feild_split[1] = feild_split[1].replace(str(num_varchar),str(num_varchar_3))    return feild_split  else:    print ('The feild type is not varchar')    return feild_splitprint (database_feild_varchar_trans(str1))

运行结果：

>>> runfile('E:/procedure/python/projects/others/table_test.py', wdir='E:/procedure/python/projects/others')The feild type is not varchar['aaa', 'varchar(10)']

以上这篇python变量不能以数字打头详解就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。

您可能感兴趣的文章:

• Python教程之全局变量用法
• 实例讲解Python中global语句下全局变量的值的修改
• 深入理解Python变量与常量
• python多进程共享变量
• python函数局部变量用法实例分析