Prompt
Turn a string into rollercoaster case. The first letter of the sentence is uppercase, the next lowercase, the next uppercase, and so on.
Code
with open('test.txt') as file:
for line in file:
words = line.split()
for word in words:
chars = list(word)
for index, char in enumerate(chars):
if index == 0:
print char.upper(),
elif is_even(index):
print char.upper(),
elif is_odd(index):
print char,
Input
Sunshine makes me happy, on a cloudy day
Output
S u N s H i N e M a K e S M e H a P p Y , O n A C l O u D y D a Y
This is my first attempt at this problem. I can't think of any other way to do this other than to iterate by each letter. When I do this though I'm just treating the entire sentence as a string and spewing out characters.
You can uppercase just every second letter with an extended slice, picking every second letter:
>>> sample = 'Sunshine makes me happy, on a cloudy day'
>>> sample[::2].upper()
'SNHN AE EHPY NACOD A'
>>> sample[1::2].lower()
'usiemksm ap,o luydy'
Now all you need to do is put those together again:
from itertools import izip_longest
result = ''.join([l
for pair in izip_longest(sample[::2].upper(), sample[1::2].lower(), fillvalue='')
for l in pair])
izip_longest()
pairs up the uppercased and lowercased strings again, making sure that if there is an odd number of characters to pad out the series with an empty string.
Demo:
>>> from itertools import izip_longest
>>> ''.join([l
... for pair in izip_longest(sample[::2].upper(), sample[1::2].lower(), fillvalue='')
... for l in pair])
'SuNsHiNe mAkEs mE HaPpY, oN A ClOuDy dAy'
Note that whitespace isn't ignored here; the m
of make
is lowercased even though the e
at the end of Sunshine
is too.
If you need to vary the letters more precisely, you can make use of iteration still:
from itertools import cycle
from operator import methodcaller
methods = cycle((methodcaller('upper'), methodcaller('lower')))
result = ''.join([next(methods)(c) if c.isalpha() else c for c in sample])
Here itertools.cycle()
lets us alternate between two operator.methodcaller()
objects , which either upper or lowercase the argument passed in. We only advance to the next one (using next()
) when the character is a letter.
Demo:
>>> from itertools import cycle
>>> from operator import methodcaller
>>> methods = cycle((methodcaller('upper'), methodcaller('lower')))
>>> ''.join([next(methods)(c) if c.isalpha() else c for c in sample])
'SuNsHiNe MaKeS mE hApPy, On A cLoUdY dAy'
If it's whitespace giving you trouble, you should use isalpha()
to test if a character is a letter or not.
with open('test.txt') as file:
for line in file:
newstr = ""
go_to_upper = True
for c in line:
if c.isalpha():
if go_to_upper:
newstr += c.upper()
else:
newstr += c.lower()
go_to_upper = not go_to_upper
else:
newstr += c
print newstr
Input: Sunshine makes me happy, on a cloudy day
Output: SuNsHiNe MaKeS mE hApPy, On A cLoUdY dAy
You'll only flip back and forth (using the go_to_upper
boolean) when the character in question is a letter of the alphabet. Otherwise, it's outputted normally. Notice that MaKeS
starts with a capital letter, though SuNsHiNe
ends with a lowercase letter, even with the space in the way.
Also, instead of printing immediately (which gives you the weird spacing) we're putting our characters in a new list, which we'll print out all at once later.
Try this code :
import re i = 1 with open('test.txt') as file: for line in file: words = line.split() for word in words: chars = list(word) for index, char in enumerate(chars): if re.compile('[a-zA-Z]').search(char): i+=1 if i%2 !=0: print char.upper(), else : print char.lower(),
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.