CODEWITHSUNDEEP
pythonnumpy
NoLand'sMan
NoLand'sMan

Reputation: 574

Selecting elements from an array based on a condition

This may be a simple question but, let us say that we have an array :

a = [0,10,20]

What is the simplest way to retrieve the least value which is greater than 0?. In this case, it would be 10.

Upvotes: 1

Views: 787

Answers (5)

Brandon
Brandon

Reputation: 126

Not pretty

a = [0, 10, 20]


def find_lowest_num(a):
    lowest_num = None
    for element in a:
        if lowest_num is None and element > 0:
            lowest_num = element
        elif lowest_num is None and element == 0:
            pass
        else:
            if element < lowest_num and element > 0:
                lowest_num = element
    return lowest_num

print(find_lowest_num(a))

Upvotes: 2

PythonLearner
PythonLearner

Reputation: 1466

I can try like this without using numpy.

def findValue():
    a = [0,10,5,20]
    a.sort()
    noToCheck = 0
    for i in a:
        if i > noToCheck :
            print("Found value: ", i)
            break

findValue()

Upvotes: 3

Austin
Austin

Reputation: 26047

Or a min on generator:

min(x for x in a if x > 0)

Example:

a = [0,10,20]

print(min(x for x in a if x > 0))
# 10

Upvotes: 3

Mykola Zotko
Mykola Zotko

Reputation: 17911

You can use the min() function with a key:

min(a, key=lambda x: float("inf") if x<=0 else x)

Upvotes: 1

Nicolas Gervais
Nicolas Gervais

Reputation: 36704

Since you included Numpy in your tags, I'm assuming you're OK with a solution with Numpy? 

import numpy as np

a = np.array([0,10,20])

np.min(a[a > 0])

Out[1]: 10

Upvotes: 2

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