>>> print(motors) ['a', 'b', '2'] >>> motors.pop(0) 'a' >>> print(motors) ['b', '2'] 若从列表中删除的元素不再使用,则使用 del语句如果删除元素还要继续使用,则使用 pop(索引) 方法,若没有索引,默认删除栈顶元素remove()pop() 和 remove() 都返回删除的元素,区别是:...
self.connected =Falseasyncdef__aenter__(self):try:print("连接数据库...")awaitasyncio.sleep(1)# 模拟连接过程self.connected =TruereturnselfexceptExceptionase:print(f"连接数据库失败:{e}")raiseasyncdef__aexit__(self, exc_type, exc_val, exc_tb):ifself.connected:print("关闭数据库连接..."...
fromastropy.coordinatesimportSkyCoordimportastropy.unitsasu# 创建天体坐标coord = SkyCoord(ra=10.68458*u.degree, dec=41.26917*u.degree, frame='icrs')print(coord.to_string('hmsdms'))# 坐标转换galactic = coord.galacticprint(f"银道坐标:{galactic.l.deg:.2f}°,{galactic.b.deg:.2f}°") Econ-AR...
with open('name.txt','a+',encoding='utf-8') as f: for line in f: print(line)#打印出每行的数据 修改文件 #把文件中所有的小写的s替换成大写的S #思路:1.打开文件,把所有的内容读取出来把小写s改为大写S # # 2.然后清空原文件内容,重新写入新的内容 with open('name.txt','a+',encoding=...
逐行扫描Line by Line 包括简单字符串处理和正则表达式方式等。 正则表达式是一个特殊的字符序列,它能方便检查一个字符串是否与某种模式匹配,Python中的re模块使Python拥有全部的正则表达式功能,其中,正则表达式的原理如下: 具体使用可参考https://www.runoob.com/python/python-reg-expressions.html。 树形模型Tree ...
Print a List with the print() Method If you want a technique that’s even easier to use than that, you can simply pass the name of the list to theprint()method by itself! You should note that the output will look a little bit different in this case. See if you can spot the diff...
# print the list by converting a list of # integers to string using map a = [ 1 , 2 , 3 , 4 , 5 ] print ( ' ' .join( map ( str , a))) print "in new line" print ( '\n' .join( map ( str , a))) 输出如下: ...
File"<stdin>", line1,in<module>ValueError:30isnotinlist>>> list_obj1.index(21)# 第一个值为21的元素位置是4,也就是第5个元素4 也可以指定开始位置。 >>>list_obj1=[1,2,4,1,21,20]>>>list_obj1.index(1,2)# 开始位置为23>>>list_obj1.index(1,0)# 开始位置为00 ...
# 使用示例 def animal_chorus(animals: List[Animal]) -> None: """演示多态性""" for animal in animals: print(animal.introduce()) if __name__ == "__main__": dog = Dog("旺财") duck = Duck("唐老鸭") # 测试继承和多态 animal_chorus([dog, duck]) # 测试多继承 print(duck.fly()...
Using this operator, you can print all the elements of the list in a new separate line with spaces in between every element using the 'sep' attribute such as sep=”/n” or sep=”,”. Check out the below example for a clear understanding of the "*" operator. Example: sample_list ...