环顾每个项目并尝试进行转换.如果转换失败，则说明它不可转换.

Loop over each item and make an attempt to convert. If the conversion fail then you know it's not convertible.

def tryconvert(s):
    try:
        return int(s)
    except ValueError:
        try:
            return float(s)
        except ValueError:
            return s

lst = ['3', '7', 'foo', '2.6', 'bar', '8.9']
newlst = [tryconvert(i) for i in lst]
print(newlst)

输出:

[3, 7, 'foo', 2.6, 'bar', 8.9]