﻿ Python: Compute the sum of the negative and positive numbers of an array of integers and display the largest sum - w3resource

# Python: Compute the sum of the negative and positive numbers of an array of integers and display the largest sum

## Python Basic - 1: Exercise-133 with Solution

Write a Python program to compute the sum of the negative and positive numbers of an array of integers and display the largest sum.

Sample Solution

Python Code:

``````def test(lst):
pos_sum = 0
neg_sum = 0
for n in lst:
if n > 0:
pos_sum += n
elif n < 0:
neg_sum += n
return max(pos_sum, neg_sum, key=abs)

nums = { 0, -10, -11, -12, -13, -14, 15, 16, 17, 18, 19, 20 };
print("Original array elements:");
print(nums)
print("Largest sum - Positive/Negative numbers of the said array: ", test(nums));
nums = { -11, -22, -44, 0, 3, 4 , 5, 9 };
print("\nOriginal array elements:");
print(nums)
print("Largest sum - Positive/Negative numbers of the said array: ", test(nums));
``````

Sample Output:

```Original array elements:
{0, 15, 16, 17, -14, -13, -12, -11, -10, 18, 19, 20}
Largest sum - Positive/Negative numbers of the said array:  105

Original array elements:
{0, 3, 4, 5, 9, -22, -44, -11}
Largest sum - Positive/Negative numbers of the said array:  -77
```

Flowchart:

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## Python: Tips of the Day

Iterating over dictionaries using 'for' loops:

I am a bit puzzled by the following code: d = {'x': 1, 'y': 2, 'z': 3} for key in d: print key, 'corresponds to', d[key] What I don't understand is the key portion. How does Python recognize ...

key is just a variable name.

```for key in d:
```

For Python 3.x:

```for key, value in d.items():
```

For Python 2.x:

```for key, value in d.iteritems():
```

To test for yourself, change the word key to poop.

In Python 3.x, iteritems() was replaced with simply items(), which returns a set-like view backed by the dict, like iteritems() but even better. This is also available in 2.7 as viewitems().

The operation items() will work for both 2 and 3, but in 2 it will return a list of the dictionary's (key, value) pairs, which will not reflect changes to the dict that happen after the items() call. If you want the 2.x behavior in 3.x, you can call list(d.items()).

Ref: https://bit.ly/37dm0Qo