迭代if函数

Question

I am currently working on a python script which will take a string, convert it to a list, and then remove all of the vowels. It then prints out the final result as a string. However, the iterative function I am using is outputting every result, whether it is a vowel or not. I have tried reversing and only keeping the consonants, but to no avail. Below is the code I was using.

string = input("#: ")
new_list = []

for x in list(string):
    if [x.lower() == y for y in list("aeiou")]:
        global new_list
        new_list.append(x)

print(''.join(new_list))

Any insight would be appreciated.

Answer 1

This line:

if [x.lower() == y for y in list("aeiou")]

creates a list with five elements (each of which is True or False ).
For instance, if x is 'e' , it will create the list

[False, True, False, False, False]

If x is not a vowel, it will create the list

[False, False, False, False, False]

Any non-empty list is true, so the if condition is satisfied.

---

What you mean to ask is "does x.lower() equals y for any y in my list of vowels?", which is this:

if any(x.lower()==y for y in list("aeiou")):

or more succinctly:

if x.lower() in "aeiou":

If you want to check if a letter is not a vowel, it would be this:

if x.lower() not in "aeiou":

Answer 2

I'm not entirely sure what did you try to do there but this does it...

string = input("#: ")
print(''.join([x for x in string if x.lower() not in "aeiou"]))

#: Hello there!
Hll thr!

An even more efficient approach would be:

print(input("#: ").translate(str.maketrans("","","aeiou")))

Answer 3

one liner show off:

string = input("#: ")
print(''.join(filter(lambda x: x.lower() in 'aeiou', string)))

References

[1] https://docs.python.org/2/library/functions.html#filter

[2] http://www.diveintopython.net/power_of_introspection/lambda_functions.html

Answer 4

First thing, a string is an iterator just like a list so no need to typecast a string to list.

s = "your_string_goes_here".lower()

s = s.replace('a', '')
s = s.replace('i', '')
s = s.replace('e', '')
s = s.replace('o', '')
s = s.replace('u', '')
print s