Python基础——拾遗（二）

Python基础——拾遗

ASCII码《==》字符

>>> chr(97)
'a'
>>> ord('a')
97

>>> [ord(c) for c in 'Wiki']
[87, 105, 107, 105]

>>> [bin(i) for i in [ord(c) for c in 'Wiki']]
['0b1010111', '0b1101001', '0b1101011', '0b1101001']

>>> [bin(i)[2:] for i in [ord(c) for c in 'Wiki']]
['1010111', '1101001', '1101011', '1101001']

assert

assert 断言后可跟两条语句，第一个是判断，第二个是断言失败时打印的错误信息（AssertionError）；

assert epsilon > 0., 'epsilon must be positive, not ' + str(epsilon)

字符串的 +（flatten） 与 .append() /.extend()

>>> a = [1, 2, 3]
>>> b = [4, 5]
>>> a + b 
[1, 2, 3, 4, 5]
>>> a.extend(b)
                    # .extend()返回值为空
>>> a 
[1, 2, 3, 4, 5]

>>> a.append(b)
                    # .append()返回值也为空
>>> a
[1, 2, 3, 4, 5, [4, 5]]