如何打印2D列表，以便每个列表都在换行符上带有空格，没有任何“”或[]

Question

I'm having trouble printing a list in a visually appealing manor. An example of the list is

[["-", "-", "-", "-"],["-", "-", "-", "-"],["-", "-", "-", "-"]] 

(the characters won't all necessarily be the same), but I need to print it without using any functions except print , range , len , insert , append , pop , and I cannot use any dictionaries or maps, or import any libraries or use any list-comprehensions. I in turn want:

- - - -
- - - - 
- - - - 

I tried:

def print_board(board): 
    for i in board: 
        row = board[i] 
        for r in row: 
            print(*row[r], "\n")

Answer 1

You're close, but you misunderstand how for i in <list> works. The iteration variable gets the list elements, not their indexes.

Also, row[r] (if r were the index) would be just a single string, not a list, so you don't need to unpack it with *row[r] .

There's no need to include "\\n" in the print() call, since it ends the output with a newline by default -- you would have to override that with the end="" option to prevent it.

for row in board:
    for col in row:
        print(col, end=" ") # print each element separated by space
    print() # Add newline

Answer 2

board = [["-", "-", "-", "-"],["-", "-", "-", "-"],["-", "-", "-", "-"]] 

for row in board:
    print(*row)

This is the easiest way, but relies on argument unpacking (that * star before the row ). If you can't use that for whatever reason then you can use the keyword arguments to print to achieve the same result

for row in board:
    for cell in row:
        print(cell, end=' ')
    print()

Answer 3

With better named variables this migh lead to better understanding:

def print_board(board): 
    for innerList in board: 
        for elem in innerList: 
            print(elem + " ", end ='') # no \n after print
        print("") # now \n


b = [["-"]*4]*4       
print_board(b)
print(b)

Output:

- - - -  
- - - -  
- - - -  
- - - -  

[['-', '-', '-', '-'], ['-', '-', '-', '-'], ['-', '-', '-', '-'], ['-', '-', '-', '-']]