Numpy and string formatting, use * to draw the shape of the field

Numpy’s character element matrix can be easily drawn; directly tearing Python strings by hand can also be completed easily.

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numpy’s character element matrix, which can be easily drawn

Use * to draw the shape of the word “田”

(Direct python string tearing by hand can also be done easily)

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Directory

◆?Use * to draw the shape of Tian character
- 1. Topic description
- 2. Algorithm analysis
- - 2.1 numpy string element matrix implementation
  - 2.2 implementation of hand-tearing python strings
  - 2.3 The simplest python code for tearing python strings by hand

◆?Use * to draw the shape of Tian character

1. Title description

Screenshot of question description

[The question comes from the CSDN Q&A community question “Use * to draw the shape of Tian”]

Back to table of contents

2. Algorithm analysis

Use * to draw the shape of a field, and both numpy and string formatting can do the job. Both methods complete the work by analyzing the shape characteristics of the drawn Tian characters, and then combining the characteristics of the tools used, design algorithms, and structural codes.

Here we focus on the implementation of string formatting; numpy implementation, after reading my previous study notes, you should be able to understand its code.

2.1 numpy string element matrix implementation

Can be completed using numpy two-dimensional array assignment
My study notes have python source code:
?
Numpy matrix frame(frame and inscribed rhombus in n×n matrix◇)
?
Changing the middle of the graph into a cross becomes the solution to the problem of this article.

The shape of Tian when x = 2~9

Only the code is posted here. To understand the code, please move to the numpy matrix frame of my study notes and click on the blue text to jump to read.

Python code for numpy implementation

#!/sur/bin/nve python
# coding: utf-8



def drawTian(n):
    import numpy as np
    a = np.full((n, n), ' ', dtype=str) # Create a character matrix.
    
    #drawing column #
    a[range(n), [0]*n] = '*'
    a[range(n), [n//2]*n] = '*'
    a[range(n), [-1]*n] = '*'
    
    #画行#
    a[[0]*n, range(n)] = '*'
    a[[n//2]*n, range(n)] = '*'
    a[[-1]*n, range(n)] = '*'
    
    print('\
'.join([" ".join(i) for i in a])) # String formatted output * field shape.


if __name__ == '__main__':

    for i in range(3, 10):
        print()
        drawTian(2*i-1)

Back to table of contents

2.2 implementation of tearing python strings by hand

Screenshot of code running effect

?
Algorithm analysis:
Carefully observe the shape of the word Tian, you can split it into 2x-1 lines, three of which have 2x-1 *_{(an English space between them)}, and the remaining lines have three * + spaces. According to this, we only need to output two types of strings, all* and three*. The three lines with all * are the first line, the last line and the middle line _{(the index subscript of the middle line is (2x-1)//2, the index subscript starts from zero, and the index of the middle line is exactly (2x-1)/ /2. For example, x = 3, (2x-1)//2 = 2; x = 3, its field shape and rows and columns are both 5*, and index 2 is the third row, which is the middle row)} , once you understand this, it will not be difficult to read the code below.

Python code for tearing strings by hand

#!/sur/bin/nve python
# coding: utf-8


def drawTian(n):
    fullStars = '* '*(n)
    fullStars = ' '.join(list('*'*(n))) # Full * lines can also look like this.
    blank = ' '*(n-2)
    threeStars = '*' + blank + '*' + blank + '*'

    for i in range(n): # String formatting loop outputs *field shape line by line.

        if i in (0, n//2, n-1):
            print(fullStars)
        else:
            print(threeStars)


if __name__ == '__main__':

    for i in range(3, 10):
        print()
        drawTian(2*i-1)

Back to table of contents

2.3 The simplest python code for tearing python strings by hand

This if statement,

        if i in (0, n//2, n-1):
            print(fullStars)
        else:
            print(threeStars)

Can be written as a print() using a ternary operation statement

        print(fullStars if i in (0, n//2, n-1) else threeStars)

String hand-shred*field "simplest code"

#!/sur/bin/nve python
# coding: utf-8


def drawTian(n):
    fullStars = '* '*(n)
    fullStars = ' '.join(list('*'*(n))) # Full * lines can also look like this.
    blank = ' '*(n-2)
    threeStars = '*' + blank + '*' + blank + '*'

    for i in range(n): # String formatting loop outputs *field shape line by line.
        print(fullStars if i in (0, n//2, n-1) else threeStars)


if __name__ == '__main__':

    for i in range(3, 10):
        print()
        drawTian(2*i-1)

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