WikiSysop: Created page with "NOTOC == Files used in example == Our favorite data file: ''ex1.dat'' == Closest to zero == There are a lot of numbers in this file. Which number is the closest to zero and where is it (row/column) ?
This is more complicated because there are both positive and negative numbers in the file.
In order to demonstrate some of the new functions/methods, I pull the entire file into memory. This problem could be solved by reading line-by-line and not keeping all the..."

2024-03-06T14:00:26Z

Created page with "__NOTOC__ == Files used in example == Our favorite data file: ''ex1.dat'' == Closest to zero == There are a lot of numbers in this file. Which number is the closest to zero and where is it (row/column) ?<br> This is more complicated because there are both positive and negative numbers in the file.<br> In order to demonstrate some of the new functions/methods, I pull the entire file into memory. This problem could be solved by reading line-by-line and not keeping all the..."

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__NOTOC__
== Files used in example ==
Our favorite data file: ''ex1.dat''

== Closest to zero ==
There are a lot of numbers in this file. Which number is the closest to zero and where is it (row/column) ?<br>
This is more complicated because there are both positive and negative numbers in the file.<br>
In order to demonstrate some of the new functions/methods, I pull the entire file into memory. This problem could be solved by reading line-by-line and not keeping all the data.
<pre>
#!/usr/bin/env python3
# Read file, keep track of where numbers are
numbers = list()
with open("ex1.dat", "r") as number_file:
line_count = 0
for line in number_file:
for field_pos, field_value in enumerate(line.split()):
try:
number = float(field_value)
numbers.append((line_count, field_pos, number))
except ValueError:
pass
line_count += 1
if len(numbers) > 0:
minimum = min(numbers, key=lambda x: abs(x[2]))
# Display Human numbers.
print(minimum[2], 'in line', minimum[0]+1, 'column', minimum[1]+1, 'is closest to 0.')
else:
print("No numbers in the file.")
</pre>
Notice how I actually don't care if all the fields are numbers, nor if there is the same amount of fields on every row.
By changing '''min''' to '''max''' I can find the number furthest away from 0.
The runtime is linear to the amount of numbers/words in the file, as I am not doing any sorting.

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