How to join these columns? (Automate the boring stuff Chapter 6 practice project)

user_12086898 0
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The practice problem asks that I arrange the nested lists in tabledata into right justified columns with one nested list each. I've figured out how to right justify every word in each column to the correct length of the column itself, but I can't figure out how to join the columns into a list instead of just printing them out as one column.

I've tried concatenating the strings in the for-loop by iterating it ahead of time (print(list[i]+list[i+1]+list[i+2]...etc), but I keep getting index out of range errors when it loops through again and increments i.

tableData = [['apples', 'oranges', 'cherries', 'banana'],
             ['Alice', 'Bob', 'Carol', 'David'],
             ['dogs', 'cats', 'moose', 'goose']]

def longlen(strings):
    maximum = 0
    for s in strings:
        if len(s) > maximum:
            maximum = len(s)
    return(maximum)

def printTable(table):
    column_width = [0] * len(table)
    for i in range(len(table)):
        column_width[i] =longlen(table[i])
        for x in range(len(table[i])):
            print(table[i][x].rjust(column_width[i]))

printTable(tableData)

Right now I am getting the correct right justification for each word, but I cant quite figure out how to output this in a 4 tall by 3 wide right justified table.

Right now it looks like this:

  apples
 oranges
cherries
  banana
Alice
  Bob
Carol
David
 dogs
 cats
moose
goose

I need this:

apples   Alice  dogs
oranges  Bob    cats
cherries Carol  moose
banana   David  goose
for-loop printing python
3 Answers

You can just modify your printTable() function:

def printTable(table):
    column_width = [0] * len(table)
    for i in range(len(table)):
        column_width[i] =longlen(table[i])
    for x in range(len(table[0])):
        for i in range(len(table)):
            print(table[i][x].rjust(column_width[i]),end=' ')
        print()

The major change is that I change your x and i positions appropriately, so that you print the 'transpose' of the list.

user_111921600

Something like this ought to work. Just for fun, I added a duck or two and the function will just output a blank item where the columns don't have the same length

tableData = [['apples', 'oranges', 'cherries', 'banana'],
             ['Alice', 'Bob', 'Carol', 'David'],
             ['dogs', 'cats', 'moose', 'duck', 'duck', 'goose']]

def printTable(table):
    # Get length of longest item in each column
    column_widths = [len(max(column, key=len)) for column in table]
    # Get longest column
    longest_col = len(max(table, key=len))
    # Major loop on each item in each nested list
    for j in range(longest_col):
        line = []
        # Nested loop over each nested list
        for i in range(len(table)):
            if j < len(table[i]):
                line.append(table[i][j].rjust(column_widths[i]))
            else:
                line.append(' '*column_widths[i])
        print('  '.join(line))

printTable(tableData)

Output:

  apples  Alice   dogs
 oranges    Bob   cats
cherries  Carol  moose
  banana  David   duck
                  duck
                 goose
user_78512720

You can do it in two steps:

  1. Go through each row and right justify each word with space characters using the built-in string method rjust() to make all of them have the same length as the longest one. To do this you'll need to first determine the longest word in the row, and that can be done using a combination of the max() and map() functions.

  2. Use the built-in zip() function to transpose the rows and columns of the table and print each row of that.

Note that as currently written, the code changes the contents of the table. If you want to avoid that, make a copy of it first.

tableData = [['apples', 'oranges', 'cherries', 'banana'],
             ['Alice', 'Bob', 'Carol', 'David'],
             ['dogs', 'cats', 'moose', 'goose']]

def printTable(table):
    for row in table:
        colwidth = max(map(len, row))
        row[:] = [word.rjust(colwidth) for word in row]

    for row in zip(*table):
        print(' '.join(row))


printTable(tableData)
user_3552300
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