str = 'Hello World!' print (str) # 输出完整字符串 print (str[0]) # 打印第一个字符 print (str[2:5]) # 打印第三到五个字符 print (str[2:]) # 输出从第三个字符到结尾 print (str * 2) # 打印两边字符串 print (str + "TEST") # Prints concatenated string