Hello all,
i'm trying to understand what should i change on my code so that i can use any words / sentence on the string:
Given a string, display only those characters which are present at an even index number.
1. My code:
Str='pynative'
a=list(Str)
print(a)
for letter in a:
index=a.index(letter)
if index % 2==0:
print('index=',index,'letter=', letter)2. The result:
Output:
['p', 'y', 'n', 'a', 't', 'i', 'v', 'e']
index= 0 letter= p
index= 2 letter= n
index= 4 letter= t
index= 6 letter= v
3. What to do to use any word and get the correct index position?
result above is ok but not suitable for example if i have a string='Hello World'.
the code does not recognize that each l occupies a different index position.
thanks in advance
frederico
Look up the enumerate function.
Also, you don't need to make a list out of the string - strings are already sequences, so can be indexed the same way as lists.
What do you want to do? I don't mean "How are you going to program", but "What do you want to do?" Can you write a concise description of what you want your program to do? That is the first step in writing a program, and that description should be the first thing you mention when asking questions about your program.
I am writing a program that prints every other letter in a string starting with the first letter (index 0). If the string is "Hello World" the output should be:
index = 0 letter = H
index = 2 letter = l
index = 4 letter = o
index = 6 letter = W
index = 8 letter = r
index = 10 letter = d
From the description you would see the solution involves calculating even numbers in the range 0 to the length of the string and using the index to get the letter. You could write this in pseudo code:
for index in range 0 to length(string)
print index and string[index]Then convert to code.
If you start with code you risk doing weird things like counting by 1 and using the modulo operator to find even numbers.
(Jul-01-2020, 01:14 PM)deanhystad Wrote: [ -> ]What do you want to do? I don't mean "How are you going to program", but "What do you want to do?" Can you write a concise description of what you want your program to do? That is the first step in writing a program, and that description should be the first thing you mention when asking questions about your program.
I am writing a program that prints every other letter in a string starting with the first letter (index 0). If the string is "Hello World" the output should be:
index = 0 letter = H
index = 2 letter = l
index = 4 letter = o
index = 6 letter = W
index = 8 letter = r
index = 10 letter = d
From the description you would see the solution involves calculating even numbers in the range 0 to the length of the string and using the index to get the letter. You could write this in pseudo code:
for index in range 0 to length(string)
print index and string[index]Then convert to code.
If you start with code you risk doing weird things like counting by 1 and using the modulo operator to find even numbers.
Thank you ! got it. i was not thinking correctly. i used what you proposed and used the Range with a step of 2 starting at 0. this solved the exercise.
You can slice the string:
>>> 'pynative'[::2]
'pntv'
Funny enough, doing this with ord (not the task) gives accidentally the same result.
"".join(c for c in 'pynative' if ord(c) % 2 == 0)
Output:
'pntv'
Coincidence?