python變數不能以數字打頭詳解

在編寫python函數時，無意中發現一個問題：python中的變數不能以數字打頭，以下函數中定義了一個變數3_num_varchar，執行時報錯。

函數如下：

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

報錯資訊如下：

>>> runfile('E:/procedure/python/projects/others/table_test.py', wdir='E:/procedure/python/projects/others')Traceback (most recent call last): File "", line 1, in  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將變數3_num_varchar改為num_varchar_3，運行成功，程式改為如下：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))

運行結果：

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

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