Splitting Array into Strings and Displaying Python

Question

So, I'm trying to take information from bookfile.txt and display information from it. So far, I've opened the file. I'm having trouble getting each line as one object of arrayBooks.

I'd like to have arrayBooks[0]="Animal Farm,1945,152,George Orwell"

Then, I'm going to use book1 = arrayBooks[0].split(',') to split it to other information, such as:

  book1[0]="Animal Farm"
  book1[1]=1945
  book1[2]=152
  book1[3]="George Orwell"

So, when I want to find the shortest book, I can compare book1[2] to book2[2] and book3[2] to do so.

My main problem is getting the information in the array and usable. Anything I've tried doesn't seem to work and gives an error in the displayAll() function.

I'm using the displayAll() as a control because I feel if I can get the information to display, I will have it to use.

---

bookfile.txt:

Animal Farm,1945,152,George Orwell

To Kill A Mockingbird,1960,324,Harper Lee

Pride and Prejudice,1813,279,Jane Austen and Anna Quindlen

---

 def main():
      print("Welcome!")
      displayBookMenu()
      populateBooks()
      displayAll(populateBooks())

 def displayBookMenu:
      print("\n1: Display All Books")
      print("2: Display Shortest Book")
      print("3: Display Longest Book")
      print("3: Display Oldest Book")
      print("4: Display Newest Book")
      print("0: End")
      choice = int(input("Choice: "))

      if choice == 1:
           displayAll()
      elif choice == 2:
           displayShortest()
      elif choice == 3: 
            displayLongest()
      elif choice == 4: 
           displayOldest()
      elif choice == 5:
           displayNewest()
      elif choice == 0:
           exit()
      else:
           print("Invalid Input")

 def populateBooks():
      fp = open("bookfile.txt", "r")
      return fp.readlines()

 def displayAll(arrayBooks):
      print ("\nAll Books: \n")
      #THIS IS WHERE I GET ERROR vvv
      print arrayBooks[0]


 def displayShortest():

 def displayLongest():

 def displayOldest():

 def displayNewest():


 main()

Answer 1

try this:

lines = [line.strip().split(',') for line in open("books.txt")]

Using list comprehesions you can read your file into a list named lines and convert each line from your files into a list of lists.

These are the results i got when i ran it:

`lines = [line.strip().split(',') for line in open("books.txt")]

print lines
print lines[2]
print lines [2][1]`
enter code here

[['Animal Farm', '1945', '152', 'George Orwell'], ['To Kill A Mockingbird', '1960', '324', 'Harper Lee'], ['Pride and Prejudice', '1813', '279', 'Jane Austen and Anna Quindlen']]
['Pride and Prejudice', '1813', '279', 'Jane Austen and Anna Quindlen']
1813

Now there are a number of edits. Here. Make sure you looks at them carefully:

`def displayBookMenu():
      print("\n1: Display All Books")
      print("2: Display Shortest Book")
      print("3: Display Longest Book")
      print("3: Display Oldest Book")
      print("4: Display Newest Book")
      print("0: End")
      choice = int(input("Choice: "))

      if choice == 1:
           displayAll(populateBooks())
      elif choice == 2:
           displayShortest()
      elif choice == 3: 
            displayLongest()
      elif choice == 4: 
           displayOldest()
      elif choice == 5:
           displayNewest()
      elif choice == 0:
           exit()
      else:
           print("Invalid Input")

def populateBooks():
      lines = [line.strip().split(',') for line in open("books.txt")]
      return lines

def displayAll(arrayBooks):
      print ("\nAll Books: \n")
      #THIS IS WHERE I GET ERROR vvv
      for books in arrayBooks:
            for each_entry in books:
                  print each_entry,
            print

def displayShortest():
      pass
def displayLongest():
      pass
def displayOldest():
      pass
def displayNewest():
      pass

def main():
      print("Welcome!")
      displayBookMenu()
      populateBooks()
main()

Remove displayBooks(populateBooks()) and instead have it in you if choice ==1 statement.

Answer 2

First, you have an error in

def displayBookMenu: #needs ()

And you can't read ArrayBooks because it'a not a global (or nonlocal) variable. I think you have problems with variable scope. Check this: Python variable scope error