How to make a change in another line by the value found in the term

Question

there are lines:

n = 'babab' m = 'metot'

new_str = 'MeToT' result: new_str = 'MeToT'

that is, if the letter 'b' in the first line, in the same place in line m letter should increase the register.

 new_str = (m[0].upper() + m[1] + m[2].upper() + m[3] + m[4].upper())

- this is not appropriate, since the places 'b' depend on the text entered by the user.

Kirill Malyshev Kirill Malyshev 5.470 one 6 22 · Accepted Answer · 2017-02-18T20:20:21

 m = 'metot' n = 'babab' new_str = '' for i in range(len(m)): new_str += m[i].upper() if n[i] == 'b' else m[i] print(new_str)

Answer 2 · 2017-02-18T20:38:06

 >>> ''.join([a.upper() if b == 'b' else a for a, b in zip('metot', 'babab')]) 'MeToT'

If the data in the numpy arrays:

 >>> a[b==b'b'[0]] &= 0x5f # upper mask >>> a.tostring() b'MeToT'

where a for example:

 >>> numpy.frombuffer(b'metot', dtype=numpy.uint8) array([109, 101, 116, 111, 116], dtype=uint8)

If the input characters are in the ascii range, this can be noticeably faster for large lines.

Answer 3 · 2017-02-18T20:20:14

Here is a primitive and certainly not the most effective solution:

 In [77]: new_str = ''.join([m[i] if c!='b' else m[i].upper() for i,c in enumerate(n)]) In [78]: new_str Out[78]: 'MeToT'

Starmap + zip solution:

 In [86]: from itertools import starmap In [87]: ''.join(starmap(lambda x,y: y if x!='b' else y.upper(), zip(n,m))) Out[87]: 'MeToT'

If you have to start lambda, then it is better to use list comprehension instead of map + lambda.
The first solution uses list comprehension , and in the second I decided to "play around" with a new function;)
If you play, then map already supports several arguments: ''.join(map(lambda x,y: y if x!='b' else y.upper(), 'babab', 'metot'))

3 answers 3