Python core Lesson 51

Question

It works but I don't know why i should ad "-1" for all lines but not for last line

file = open("/usercode/files/books.txt", "r")

for f in file:
if not (len(f) ==18):
print (f[0] + str((len)(f)-1))
else:
print (f[0] + str((len)(f)))

file.close()

Answer 1

Матвей Стаселько ,

the code you are presenting is "hard-coded" as it only checks if length is a value of 18

what you can do:

▪︎in your code, the variable 'f' contains the respective string from the file in each iteration cycle of the for loop. all lines (exept the last ones) coming from the file are terminated with a newline- sequence. this can be removed from the string by using strip() like f.strip(). if there is no new-line sequence nothing happens.

▪︎strip removes all kind of whitespace. this can be a simple space, as well as a new-line sequence.

happy coding and good success!

Answer 2

Матвей Стаселько ,

taking the code from Alex and do some changes:

file = open("/usercode/files/books.txt", "r")

for line in file:
print(line[0] + str(len(line.strip())))

file.close()

Answer 3

Матвей Стаселько ,

practicing is important to grow the coding skills. try to solve simple tasks in simple and clear code. after some time you may go back to your code and try to improve it. always keep in mind that a good readability is the key point for maintaining code.

an other way to improve your ability is reading codes from other people, like in playground, or in the q&a section. take codes that people have posted and also raised a question to it. try to find a solution first without having a look what people have posted. then later on have a look at their solutions

not to forget websites like geeksforgeeks, tutorialspoint and others. also see realpython, which have a lot of free tutorials. to get dedicated answers, stackoverflow is the one of the best sources.

as reading in the web can sometimes be tiring, also have a look at videos from YouTube. try to find what suits you best

happy coding and good success!

Answer 4

Each line has a newline character appended to it except last line(obviously)

Answer 5

Thank you!
Now I get it!

Answer 6

Abhay,

How can I add last line for "else" if I don't know the lenght of this line for example?

Answer 7

Матвей Стаселько sorry buy i don't understand what you mean by not knowing the length of last line . Anyway ,Why do you need to know the length of last line ?

Answer 8

Lothar,
Which line I should add strip()?

Answer 9

Add strip to every line . rstrip() will remove white spaces(including newline) from the end of line .

Answer 10

Матвей Стаселько you don't need to strip from the f[0] unless question says so.
Strip from the one that you are getting length of.

and honestly i won't even use strip since you don't know if the white space was deliberately put there or not.

Just use rstrip.

Answer 11

file = open("/usercode/files/books.txt", "r")

for i in file:
new_list = i.strip()
print(new_list[0] + str(len(new_list)))

file.close()

Answer 12

Lothar,
Yes, i have already done like this
Thanks for helping!

Answer 13

Abhay,
When I do like this
There are no any changes
Last line still less than needed:(

file = open("/usercode/files/books.txt", "r")

for f in file:
print (f[0].strip() + str(len(f)))

file.close()

Answer 14

Lothar

I started learning programming some days ago
But I understand that SoloLearn's lessons isn't enough to do a lot of things
Can You give an advice what i should to read to become more skillful?
Sorry for disturbing you

Answer 15

I actually don't know what is happening help me out

Answer 16

file = open("/usercode/files/books.txt", "r")

#your code goes here
for line in file:
print(line[0]+ str(len(line.strip("\n"))))

file.close()

Answer 17

Yes, this answer works but will not work if the list is ever added to. Up to this point, SoloLearn has not taught the strip() function. Would there be a way to do this code project without it?

Answer 18

Here is my code:

file = open("/usercode/files/books.txt", "r")

#List of books
books = file.readlines()
#print(books)

#Qty of rows
qty_rows = len(books)
#print(qty_rows)

#First letter of book / first char in each row
#for i in range(qty_rows):
# print(books[i][0])

#Qty chars in each row
#for i in range(qty_rows):
# row = books[i]
# l_row = len(row)
# print(l_row)

for i in range(qty_rows):
row = books[i]
l_row = len(row)
if i != qty_rows-1:
print(books[i][0] + str(l_row - 1))
else:
print(books[i][0] + str(l_row))

file.close()

Is it OK?