Strings can beconcatenatedto build longer strings using the plus sign and also they can bemultipliedby a number, which results in the continuous repetition of the string as many times as the number indicates. Also, if we want to find out thelengthof the string, we simply have to use thelen...
假设我们要从远程 API 读取数据,普通方式会让代码等待 API 响应,阻塞整个程序,而协程可以让我们在等待数据时处理其他任务: importasyncioimportaiohttpasyncdeffetch_data(url):asyncwithaiohttp.ClientSession()assession:asyncwithsession.get(url)asresponse:data=awaitresponse.text()# 异步等待API返回数据print(f"收...
print(int('1.234'))#报错 print(eval('1.234'))可以print(int(1.234))#可以 字符串的常用方法 实例 a='thank you'print(a.capitalize())print(a.center(20))print(a.center(20,'\''))print(a.endswith('s'))print(a.find('o')) # 返回第一个o位置的下标 7print(a.rjust(20,'+')) 注意 ...
print(n+2)print(n+3) 1920 它同样适用于浮点数和字符串。 print('The value of pi is approximately')print(math.pi) The value of piisapproximately3.141592653589793 你还可以使用由逗号分隔的表达式序列。 print('The value of pi is approximately', math.pi) The value of piisapproximately3.1415926535897...
print("输入不是有效数字") except ZeroDivisionError: print("错误:除数不能为零") 1. 2. 3. 4. 5. 6. 7. 8. 2. 捕获多个异常 try: file = open("nonexistent.txt", "r") data = file.read() num = int(data) except (FileNotFoundError, ValueError) as e: ...
for i in [0, 1, 2, 3]: print(i) 前面的for循环实际上遍历了它的子句,变量i在每次迭代中被设置为[0, 1, 2, 3]列表中的一个连续值。 一种常见的 Python 技术是使用range(len(someList))和for循环来迭代列表的索引。例如,在交互式 Shell 中输入以下内容: >>> supplies = ['pens', 'staplers'...
""" pass def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__ """ S.rsplit(sep=None, maxsplit=-1) -> list of strings Return a list of the words in S, using sep as the delimiter string, starting at the end of the string and working to...
print(lines) # 输出:['第一行\n', '第二行\n', ...] 1. 2. 3. 4)文件写入操作 1. 覆盖写入 with open('output.txt', 'w', encoding='utf-8') as f: f.write("Hello, World!\n") # 写入字符串 f.writelines(["第一行\n", "第二行\n"]) # 写入列表(不自动添加换行符) ...
When converting a string to list of characters, whitespaces are also treated as characters. Also, if there are leading and trailing whitespaces, they are part of the list elements too. s = 'abc$ # 321 ' print(f'List of Characters ={list(s)}') Copy Output: List of Characters =['...
Access String Characters in Python We can access the characters in a string in three ways. Indexing:One way is to treat strings as alistand use index values. For example, greet ='hello'# access 1st index elementprint(greet[1])# "e" ...