Python 3.43：制作网格并使用sys.stdout.write（）

Question

I understand this has most likely been asked before, I am just hoping to get some insight after hours of searching. I am attempting to make a grid using python 3.43.

+ - - + - - +
|     |     |
|     |     |
+ - - + - - +
|     |     |
|     |     |
+ - - + - - +

This is my code thus far, and I successfully have the first 4 columns and 7 rows. The trouble is extending this to be a pattern, to make two more connecting boxes to make a grid.

print ('#1')
corner = '+'
bar = ' -'
side = '|'
space = ' '

top_row = corner + bar + bar + space + corner
sides = side + space*5 + side

def do_twice(func,arg):
    func(arg)
    func(arg)

def sides(width):
    sides = side + (space * width) + side
    print (sides)

def top(length):
    top_row = corner + (bar * length) + space + corner
    print(top_row)


top(2)
do_twice(sides,5)
top(2)
do_twice(sides,5)
top(2)

This gives me one side of the grid. To those who are experienced in python, it may seem rudimentary but I'm just trying to grasp the basics. What I have tried to do to add the other side for the top row is:

import sys
def top(length):
    top_row = corner + (bar * length) + space + corner
    print(top_row),(sys.stdout.write(' - - +'))

It actually helps, but it returns "None" at the end, and I beleive this is because I am essentially printing twice, but my intention is to just add on text to the same line. The result is this:

+ - - + - - + None
|     |
|     |
+ - - + - - + None
|     |
|     |
+ - - + - - + None

Anyone have any ideas as to how I can either extend this function or another method to print on the same line?

I really appreciate it, and thank you for your time.

Answer 1

Try:

left = corner + (space + bar)*length + space
top = left + corner + left[::-1]
print(top)

The [::-1] reverses the string and the left half of your grid is the reflection of the right half, but with a corner in the middle.

You were right with about why you had a None in there. I recommend against using print and sys.stdout.write in the same place since they're the same thing and would make your code unnecessarily confusing.

There should be one-- and preferably only one --obvious way to do it.

-The Zen of Python, Tim Peters

Answer 2

In Python 3.x, print() takes an 'end' parameter that tells the function what to print after it has printed all it's arguments. The parameter defaults to '\\n', so that the function moves to the next line after printing. If you want to keep printing on the same line, simply use end=''.

print('1234', end='')
print('ABCD')           #  should print 1234ABCD

Regarding making a grid, you seem to know that multiplying a string by an integer repeats the string (eg, bar * length => ' - -').In Python 3.x, print() takes an 'end' parameter that tells the function what to print after it has printed all it's arguments. The parameter defaults to '\\n', so that the function moves to the next line after printing. If you want to keep printing on the same line, simply use end=''.

print('1234', end='')
print('ABCD')           #  should print 1234ABCD

About making a grid: You seem to know that multiplying a string by an integer repeats the string (eg, bar * length => ' - -'). You also seem to recognize that you can extend the line by adding ' - - +'. Put these ideas together and you get:

cell_width = 2
grid_width = 3

hpart = bar*cell_width + space + corner  # -> ' - - +'
hline = corner + hpart*grid_width        # -> '+ - - + - - + - - +'

The same technique can be used to make the vertical lines:

'|     |     |     |'

and then a row part:

'|     |     |     |\n'
'|     |     |     |\n'
'+ - - + - - + - - +\n'

and then the grid is hline + row_part*grid_height.