DeBug Python神级工具PySnooper

安装

pip3 install pysnooper

import pysnooper

@pysnooper.snoop()
def number_to_bits(number):
    if number:
        bits = []
        while number:
            number, remainder = divmod(number, 2)
            bits.insert(0, remainder)
        return bits
    else:
        return [0]

number_to_bits(6)

返回日志

Starting var:.. number = 6
21:14:32.099769 call         3 @pysnooper.snoop()
21:14:32.099769 line         5     if number:
21:14:32.099769 line         6         bits = []
New var:....... bits = []
21:14:32.099769 line         7         while number:
21:14:32.099769 line         8             number, remainder = divmod(number, 2)
New var:....... remainder = 0
Modified var:.. number = 3
21:14:32.099769 line         9             bits.insert(0, remainder)
Modified var:.. bits = [0]
21:14:32.099769 line         7         while number:
21:14:32.099769 line         8             number, remainder = divmod(number, 2)
Modified var:.. number = 1
Modified var:.. remainder = 1
21:14:32.099769 line         9             bits.insert(0, remainder)
Modified var:.. bits = [1, 0]
21:14:32.099769 line         7         while number:
21:14:32.099769 line         8             number, remainder = divmod(number, 2)
Modified var:.. number = 0
21:14:32.099769 line         9             bits.insert(0, remainder)
Modified var:.. bits = [1, 1, 0]
21:14:32.099769 line         7         while number:
21:14:32.099769 line        10         return bits
21:14:32.099769 return      10         return bits

PySnooper特征

如果标准错误输出难以获得，或者太长了，那么可以将输出定位到本地文件：

@pysnooper.snoop('/my/log/file.log')

查看一些非本地变量的值：

@pysnooper.snoop(variables=('foo.bar', 'self.whatever'))

展示我们函数中调用函数的 snoop 行：

@pysnooper.snoop(depth=2)

将所有 snoop 行以某个前缀开始，更容易定位和找到：

@pysnooper.snoop(prefix='ZZZ ')

更可以用来获取TensorFlow 的各种张量信息，十分强大