(name order by name desc))),',') AS all_name FROM student GROUP BY id; # case语句 case var when condition1 then statement1 when condition2 then statement2 else statementn end as new_name 比如: select case name when '小明' then 'xm' when '小红' then 'xh' when '小刚' then 'xg...
而为了保证线程安全性,整个过程加了 Condition 锁,连接池的构造参数 blocking 就是用来决定在此时一旦获取锁失败是否阻塞等待的。 9. 连接的使用 9.1. 构造方法 def __init__(self, pool, con) PooledDedicatedDBConnection 与 PooledSharedDBConnection 两个连接类的构造方法都需要传入连接池对象与一个 DB 操作...
def lst_condition(): lst = [0, 1, 0, 3] print [a if a else 2 for a in lst] # change 0 -> 2 # [2, 1, 2, 3] print ["ha" if i else "Ha" for i in range(3)] # ['Ha', 'ha', 'ha'] def lst_delete_in_for_loop(): lst = [0, 1, 0, 3] for item in ls...
add_state(OldState, [have([X|Haves])|Temp], have, X) :-delete(have(Haves), OldState, Temp). add_state(OldState, [status([Thing/Stat|TempStats])|Temp],status, Thing/Stat) :-delete(status(Stats), OldState, Temp),delete(Thing/_, Stats, TempStats). % end condition end_condition(...
def delete_Row(grid, occupied): # check if the row is occupied or not black_background_color = (0, 0, 0) number_of_rows_deleted = 0 for i in range(len(grid)-1,-1,-1): eachRow = grid[i] if black_background_color not in eachRow: number_of_rows_deleted += 1 index_of_de...
Python开发常用组件、命令(干货) 1、生成6位数字随机验证码 import random import string def num_code(length=6): """ 生成长度为length的数字随机验证码 :param length: 验证码长度 :return: 验证码 """ return ''.join(random.choice(string.digits) for i in range(0, length)) ...
To handle the error when the table already exists, we notify the user that it was already there. Other errors are printed, but we continue creating tables. (The example shows how to handle the “table already exists” condition for illustration purposes. In a real application, we would ...
Use the following example AWS SDK for Python (Boto3) code to list the models that you've trained, to query a model's metadata, and to delete a model that you no longer want to use. If you've used label data when you created a dataset, you can also use this code to see how ...
# .when(condition) ## the UiSelector condition of the watcher. # .click(target) ## perform click action on the target UiSelector. There is also a trick about click. You can use click without arguments. d.watcher("ALERT").when(text="OK").click() # Same as d.watcher("ALERT").wh...
import requests METHODS = ['GET', 'POST', 'HEAD', 'TRACE', 'PUT', 'DELETE', 'OPTIONS', 'CONNECT', 'PATCH'] # 可以不使用--- class HTTPClient (object): def __init__(self, url, method='GET', headers=None, cookies=None): """headers: 字典。 例:headers={'Content_Type':'text...