Python list Merging

Question

I am getting list output like this, I want to make clear separation between lists so that I can access each list separately how do I do that

for Book in rootNode.getBooks():
    CompareTables=[]
    CompareTables.append(Book.getName())
    for Table in Book.getTables():
        CompareTables.append(Table.getName())
    print CompareTables

Output:

['Document', 'A','B','C']
['Document', 'A','B','C','D','E','F']

I want output like this:

print CompareTables1

Output:

 ['Document', 'A','B','C']

print CompareTables2

 ['Document', 'A','B','C','D','E','F']

Would you mind explaining a little more? If I understand you, the goal to do the printing after the loop rather than inside the loop, is that right? — minopret
– minopret, Commented Mar 19, 2013 at 11:53
It doesnt matters as now when i am printing CompateTables its giving me different lists, that is ok, but I want to access them by different names as I want to compare elements in them — rgerts
– rgerts, Commented Mar 19, 2013 at 11:58

Jon Clements · Accepted Answer · 2013-03-19 12:49:25Z

3

Create a new list to add your per-book lists to:

all_compare_tables = []
for Book in rootNode.getBooks():
    CompareTables=[]
    CompareTables.append(Book.getName())
    for Table in Book.getTables():
        CompareTables.append(Table.getName())
    all_compare_tables.append(CompareTables)

print all_compare_tables[0]
print all_compare_tables[1]

# better yet, loop:

for compare_tables in all_compare_tables:
    print compare_tables

Alternatively, you could use a dictionary:

all_compare_tables = {}
for i, Book in enumerate(rootNode.getBooks(), 1):
    CompareTables=[]
    CompareTables.append(Book.getName())
    for Table in Book.getTables():
        CompareTables.append(Table.getName())
    all_compare_tables['CompareTables{}'.format(i)] = CompareTables

The above example generates keys as CompareTables1, CompareTables2, etc. but perhaps you had better names in mind.

Printing these then becomes:

print all_compare_tables['CompareTables1']
print all_compare_tables['CompareTables2']

or loop over the all_compare_tables.keys() or all_compare_tables.values() sequences.

edited Mar 19, 2013 at 12:49

Jon Clements

143k34 gold badges254 silver badges288 bronze badges

answered Mar 19, 2013 at 11:49

Martijn Pieters

1.1m326 gold badges4.2k silver badges3.4k bronze badges

Sign up to request clarification or add additional context in comments.

23 Comments

rgerts Over a year ago

[['Document','A','B','C' ]] [['Document', 'A','B','C','D','E','F']]

rgerts Over a year ago

any more help? They still seems to be same, I want to have access them separtely

Martijn Pieters Over a year ago

@AbhishekSharma: I don't think you executed my code correctly; you seem to have created multiple all_compare_tables lists inside of your loop.

rgerts Over a year ago

No change its still the same print all_compare_tables['CompareTables1'] gives me both tables

Martijn Pieters Over a year ago

@AbhishekSharma: and you are using the exact same code as in my samples? I very much doubt that you are. Please do doublecheck you are not creating the CompareTables list outside of the loop, for example.

|

Emmanuel · Accepted Answer · 2013-03-19 11:51:42Z

0

Well, a dict is made for such cases:

CompareTables = {}
for Book in rootNode.getBooks():
    book_name = Book.getName()
    CompareTables[book_name] = []
    for Table in Book.getTables():
        CompareTables[book_name].append(Table.getName())
    print CompareTables

Here your 2 books seem to have same title Document, so you can use an index to differentiate them:

CompareTables = {}
for i, Book in enumerate(rootNode.getBooks(), 1):
    book_name = Book.getName() + str(i)
    CompareTables[book_name] = []
    for Table in Book.getTables():
        CompareTables[book_name].append(Table.getName())
    print CompareTables

answered Mar 19, 2013 at 11:51

Emmanuel

14.2k12 gold badges53 silver badges73 bronze badges

10 Comments

rgerts Over a year ago

{'Document1': ['A','B','C']} {'Document1': ['A','B','C','D','E','F']} STILL I CAN'T DISTINGUIS THEM

Emmanuel Over a year ago

@Martijn: this is why I added the 2nd part ! Are you sure you read my post entirely ?

rgerts Over a year ago

@Emmanuel: Print CompareTables is giving me both list, I want to make them separately accessible by two different list name

rgerts Over a year ago

It seems my value of i is not increasing, every time it prints Document1 for both files

rgerts Over a year ago

Because If a change value of i from 1 to 2 in loop, it changes the value to Document2, Document 2 in both, any suggestions?

|

Collectives™ on Stack Overflow

Python list Merging

2 Answers 2

23 Comments

10 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

23 Comments

10 Comments

Your Answer

Sign up or log in

Post as a guest

Related