I would like to get input from a user and then to print the string reversed like this:
input:
hello
output:
o
ol
oll
olle
olleh
This is my code:
s = input()
for i in range(len(s) - 2, -1, -1):
print(s[:i:-1])
And output i receive is:
o
ol
oll
olle
I am constantly missing the last character. I tried many variations of the slicing. What am I missing?
You must first obtain the substring and then reverse it:
s = "hello"
for i in range(len(s)-1, -1, -1):
print(s[i:][::-1])
Or:
s = "hello"
for i, _ in enumerate(s):
print(s[i:][::-1])
Or reverse the word and get the substring:
s = "hello"
for i, _ in enumerate(s):
print(s[::-1][:i+1])
To get the full string reversed you must use s[::-1] omitting the first value.
Since that doesn't fit into your iteration you'll have to use something like:
s = input()
for i in range(len(s) - 2, -1, -1):
print(s[:i:-1])
print(s[::-1])
Easiest perhaps is to iterate from -1 backwards:
s = 'hello'
for i in range(1, len(s)+1):
print(s[-1: -i-1: -1])
hello
o
ol
oll
olle
olleh
The way this works, you are slicing sequentially:
s[-1: -2: -1],s[-1: -3: -1],...s[-1: -len(s)-1: -1]I would do it this way:
a = "Hello"
for i in range(len(a)):
print(a[-i-1])
This way you are not dealing with string slices, only indexing the string and there isn't a bunch of extra numbers to figure out what they are doing.
You could also simply reverse the complete thing and print it sliced from the start to save you some headache:
b = "hello" # your input
h = b[::-1] # inverse all - so this is now olleh
# list slicing is from:exclusive to - so simply add 1 to fit with the ranges values 0-4
for k in ( h[0:i+1] for i in range(0,len(h)) ):
print(k)
Output:
o
ol
oll
olle
olleh
The very basic method to reverse a string s is s[::-1] (and save it
in another variable, say s2).
Then, to print consecutive rows with increasing part of this string (s2),
you need a loop over range(1, len(s2)+1), stating the upper limit of s2
(excluding).
So the script can look like below:
s = 'hello'
s2 = s[::-1]
for i in range(1, len(s2)+1):
print(s2[:i])
