How to capitalize only first letter of first word in a list

Question

I want to capital only first letter of first word of list and remaining all words to be in lower case in ascending order of the length of word.

z=['The' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
z.sort(key=len) 
print(" ".join(x.lower() for x in z))

I want the result like this in ascending order of length.

In the are lines order printed reverse :

z=['The' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
# i tried like this 
z.sort(key=len)
s=[]
for x in z:
     if (x==0):
        s.append(z[0].capitalize())
     else:
        s.append(z[x].lower())

Actual output that I am trying to get:

In the are lines order printed reverse

Answer 1

Your code

for x in z: # ['in', 'The', 'are', 'lines', 'order', 'printed', 'reverse'] if (x==0): s.append(z[0].capitalize()) else: s.append(z[x].lower())

does not work because each x is a word from z - it will never be equal to 0 so all that things added to s are lower case version of your words.

---

You can use enumerate to get the index of all elements in the list while iterating it.

The first element has to use .title() casing, all others .lower() :

z= ['The' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
z.sort(key=len) 

# reformat capitalization based in index, any number != 0 is true-thy
z = [ a.lower() if idx else a.capitalize() for idx, a in enumerate(z) ]

print(" ".join(z))

Output:

In the are lines order printed reverse

---

z = [ a.lower() if idx else a.capitalize() for idx, a in enumerate(z) ] is a list comprehension - as normal loop it would look like:

s = []
for idx, word in enumerate(z):
    if idx:   # any idx > 0 is True-thy
        s.append(word.lower())
    else:
        s.append(word.capitalize())
# print the joined s 

You can learn what python considers True for non-boolean values here: Truth-value-testing

Answer 2

You don't need to use a for loop (or enumerate ), you can just use the capitalize() method if you're sure the type of the first value will always be str .

In other words, call the capitalize() method on the first value of the list and change the value at index 0 to its result.

For example, the following code:

z = ['the' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
z.sort(key = len)
z[0] = z[0].capitalize()
print(z)

Should output:

['In', 'the', 'are', 'lines', 'order', 'printed', 'reverse']

And if you join it using a space, like this:

z = " ".join(z)

It'll output:

'In the are lines order printed reverse'

WARNING: if you do decide to use join on z , you'll be changing its type from list to str , indexes will still work but z[0] will no longer equal In , it'll be I .

---

If you want to be extremely thorough and ensure that all other words are lower cased, you can use the following list comprehension instead of the aforementioned technique:

z = ['the' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
z.sort(key = len)
z = [(x.capitalize() if i == 0 else x) for (i, x) in enumerate(z)]

Expected output:

['In', 'the', 'are', 'lines', 'order', 'printed', 'reverse']

Output when joined using " ".join(z) :

'In the are lines order printed reverse'

Good luck.

Answer 3

Here is the Basic answer output expected by you. you have to call the capitalize() method for the first value in the list and change its value at index 0 to capital.

Here is a basic code to do so

list = ['the' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
list.sort(key = len)
list[0] = list[0].capitalize()
print(list)

Output will be i the form of an array:

['In', 'the', 'are', 'lines', 'order', 'printed', 'reverse']

to get it in the form of a sentence you can try the code below

list = ['the' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
list.sort(key = len)
list[0] = list[0].capitalize()
print(" ".join(list))

Output Will be

In the are lines order printed reverse

" ".join(list) Just the list in form of space to convert the output in the form of list to a sentence

Answer 4

I wrote this simple code, I know it's not the most concise but it does the job:

z=['The' ,'lines', 'are', 'printed', 'in', 'reverse', 'order']
s=[]
for x in z:   
    wordup=(x[0].upper() + x[1:len(x)]) 
    s.append(wordup)
print(s)

x is not an integer, we are iterating strings x from the list z

wordup is the concatenation of the first letter of (x) capitalized, and the rest of (x) : this means from index 1 to end of x (len(x))

Using the 'capitalize()' method:

z=['in', 'The', 'are', 'lines', 'order', 'printed', 'reverse']
s=[]
for x in z: 
    s.append(x.capitalize())
print(s)