s2='we are chinese'分别提取"we"和"are"两个子串

可以使用字符串的 split() 方法实现：

s2 = 'we are chinese'
substrings = s2.split(' ')
print(substrings[0]) # 输出 we
print(substrings[1]) # 输出 are

或者使用字符串的切片操作：

s2 = 'we are chinese'
sub1 = s2[0:2] # 切片，提取前两个字符
sub2 = s2[3:6] # 切片，提取中间的三个字符
print(sub1) # 输出 we
print(sub2) # 输出 are