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Python

格式化输出

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print("output:", a, b)
print(f"output: {a} {b}")
print("output: {} {}".format(a, b))

切片

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>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> a[2:3]
[2]
>>> a[5:9]
[5, 6, 7, 8]
>>> a[5:-1]
[5, 6, 7, 8]
>>> a[-5:9]
[5, 6, 7, 8]
>>> a[-5:-1]
[5, 6, 7, 8]
>>> a[:5]
[0, 1, 2, 3, 4]
>>> a[5:]
[5, 6, 7, 8, 9]
>>> a[100:]
[]

扩展切片 a[start:stop:step]：

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>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> a[0:6:2]
[0, 2, 4]
>>> a[::2]
[0, 2, 4, 6, 8]
>>> a[:-2:2]
[0, 2, 4, 6]
>>> a[4::2]
[4, 6, 8]
>>> a[5::-1]
[5, 4, 3, 2, 1, 0]
>>> a[:4:-2]
[9, 7, 5]
>>> a[::-1]
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]