Python: Print a heap as a tree-like data structure
Python heap queue algorithm: Exercise-19 with Solution
Write a Python program to print a heap as a tree-like data structure.
Sample Solution:
Python Code:
import math
from io import StringIO
#source https://bit.ly/38HXSoU
def show_tree(tree, total_width=60, fill=' '):
"""Pretty-print a tree.
total_width depends on your input size"""
output = StringIO()
last_row = -1
for i, n in enumerate(tree):
if i:
row = int(math.floor(math.log(i+1, 2)))
else:
row = 0
if row != last_row:
output.write('\n')
columns = 2**row
col_width = int(math.floor((total_width * 1.0) / columns))
output.write(str(n).center(col_width, fill))
last_row = row
print (output.getvalue())
print ('-' * total_width)
return
#test
import heapq
heap = []
heapq.heappush(heap, 1)
heapq.heappush(heap, 2)
heapq.heappush(heap, 3)
heapq.heappush(heap, 4)
heapq.heappush(heap, 7)
heapq.heappush(heap, 9)
heapq.heappush(heap, 10)
heapq.heappush(heap, 8)
heapq.heappush(heap, 16)
heapq.heappush(heap, 14)
show_tree(heap)
Sample Output:
1 2 3 4 7 9 10 8 16 14 ------------------------------------------------------------
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Python: Tips of the Day
Find current directory and file's directory:
To get the full path to the directory a Python file is contained in, write this in that file:
import os dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
- The os and os.path modules.
- The __file__ constant
- os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
- os.path.dirname(path) (returns "the directory name of pathname path")
- os.getcwd() (returns "a string representing the current working directory")
- os.chdir(path) ("change the current working directory to path")
Ref: https://bit.ly/3fy0R6m
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