我需要在我的 python 脚本中添加尝试，但不知道如何去做答案

【问题标题】：i need to add try in my python script but not sure how to go about it我需要在我的 python 脚本中添加尝试，但不知道如何去做
【发布时间】：2021-01-20 22:59:05
【问题描述】：

我需要在我的脚本中添加尝试，以便当输入为空白或错误时，它会在不显示空白表格但不知道如何操作的情况下这么说，将不胜感激

import mysql.connector
from prettytable import PrettyTable
username = input('what user are you looking for?: ')
bd = mysql.connector.connect(host="localhost", user="root", password="", database="comptes_linux")
cursor = bd.cursor()
cursor.execute("SELECT * FROM users WHERE user LIKE %s", [username])
resultat = cursor.fetchall()
x = PrettyTable()
x.field_names = ["User","Filler","Uid","Gid","Gecos","Home","Login"]
x.align["User"]  = "l"
x.align["Gecos"] = "l"
x.align["Home"]  = "l"
x.align["Login"] = "l"
x.align["Uid"]   = "r"
x.align["Gid"]   = "r"
x.add_rows(resultat)
print(x)
cursor.close()
bd.close()

【问题讨论】：

标签： python mysql try-catch

【解决方案1】：

我输入了一个 if 语句，还输入了“try:..except”以防止进一步的错误：

import mysql.connector
from prettytable import PrettyTable
username = input('what user are you looking for?: ')
if not username:
    print("Please enter a valid username")

else:    
    try:
        bd = mysql.connector.connect(host="localhost", user="root", password="", database="comptes_linux")
        cursor = bd.cursor()
        cursor.execute("SELECT * FROM users WHERE user LIKE %s", [username])
        resultat = cursor.fetchall()
        x = PrettyTable()
        x.field_names = ["User","Filler","Uid","Gid","Gecos","Home","Login"]
        x.align["User"]  = "l"
        x.align["Gecos"] = "l"
        x.align["Home"]  = "l"
        x.align["Login"] = "l"
        x.align["Uid"]   = "r"
        x.align["Gid"]   = "r"
        x.add_rows(resultat)
        print(x)
        cursor.close()
        bd.close()
    except:
        print("Couldn't find ",username)

“If not username”应该检测到空输入，如图here

【讨论】：

这无济于事，因为空输入会产生错误
@nbk 我现在已经更改了它。这希望现在可以工作，尽管很难回答，因为我只有用户提供的代码。

【解决方案2】：

只有在您输入任何用户名时才会继续。

它还会检测错误并向您显示错误

import mysql.connector
from prettytable import PrettyTable
try:
  username = input('what user are you looking for?: ')
except SyntaxError:
  username = None
  print(username)
if username is not None and username != '':
  try:
    bd = mysql.connector.connect(host="localhost", user="root", password="", database="comptes_linux")
    cursor = bd.cursor()
    rows_count = cursor.execute("SELECT * FROM users WHERE user LIKE %s", [username])
    if rows_count > 0:
      resultat = cursor.fetchall()
      x = PrettyTable()
      x.field_names = ["User","Filler","Uid","Gid","Gecos","Home","Login"]
      x.align["User"]  = "l"
      x.align["Gecos"] = "l"
      x.align["Home"]  = "l"
      x.align["Login"] = "l"
      x.align["Uid"]   = "r"
      x.align["Gid"]   = "r"
      x.add_rows(resultat)
      print(x)
      cursor.close()
      bd.close()
    else:
      print("username not found")
  except Exception as e:
    print("error: " + str(e))
else:
  print("username is empty")

【讨论】：