Digit Conversion Function X27470

Statement

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Write a function conv_dig(test, conv) that returns a digit conversion function. The returned function takes a positive integer n and returns a new integer where each digit d of n that passes the test (test(d) == True) is replaced by its conversion conv(d). Digits of n that do not pass the test are to be left unchanged by the digit conversion function.

Input

Output

Observation

Let us insist that the digit conversion function described is not the required conv_dig proper, but its output.

Sample session

>>> conv_dig_func = conv_dig(lambda d: d % 2 == 0, lambda d: d // 2)
>>> conv_dig_func(21098)
11094
>>> conv_dig_func(1032547698)
1031527394
>>> conv_dig_func = conv_dig(lambda d: d < 5, lambda d: 2)
>>> conv_dig_func(1064592)
2262592
>>> conv_dig_func(9876543210)
9876522222

Information

Author: Jordi Delgado and José Luis Balcázar
Language: English
Official solutions: Python
User solutions: Python