I have a float number x and a list range list_ = [[a, b], [c,d], [e,f]]

How can check if the number x is in the list. It means the function will return True in case of

a<=x <=b
or 
c<=x <=d
or 
e<=x <=f

Otherwise, the function will return False. Could you help me to write a Python code for the function

function (x, list_)--> True/False

CodePudding user response：

The idiomatic solution would be this:

def f(x: int, ls: List[Tuple[float, float]]) -> bool: 
   return any(a <= x <=b for (a, b) in ls)

Take specific note of the following:

• Naming a function function is a super poor idea.
• It is abnormal and therefore a poor idea to name a variable list_ just to avoid overriding a keyword.
• Using the form any ensures that you quickly quit when you find a valid solution.
• You can quickly destructure your tuple (or list, if you happen to pass a list) using the for (a, b) in ls clause.
• This solution is as quick as if you use a for clause, but all of that is premature optimization anyway.
• Using an explicit destructing ensures you have two and only two elements for your sublist.

It was requested that I check certain inputs:

>>> f(10.1, [[8.1, 12.1], [110, 120]])
True

Seems to work!

If you're running into NameError, the issue is simply one of the importation of types. You can either define f like so:

def f(x, ls):
    ... // As you would otherwise

Or import the required types to make the type-hinting work properly:

from typing import List, Tuple
def f(x: int, ls: List[Tuple[float, float]]) -> bool: 
    ... // As you would otherwise

This has little to do with the original question or solution - it's just standard for type hinting in python.

CodePudding user response：

Clean solution:

def function(x, list_):
    return any([l[0] < x < l[1] for l in list_])

Optimized solution:

def function(x, list_):
    for l in list_:
        if l[0] < x < l[1]:
           return True
    return False

CodePudding user response：

def function(x,list__):
    for [a,b] in list_data:
        if a<=x<=b:
            return True
    return False

CodePudding user response：

You can simply iterate through the list and find whether it's in range or not.

I'm generating the variable and the list randomly and calling a function that iterates and checks whether the variable lies within the range of any of the members of the list.

import numpy as np

def find_if_in_range(list_, var) -> bool:
    for i in list_:
        if i[0] <= var <= i[-1]:
            return True
    return False

var = np.random.randint(10)
list_ = np.random.randint(10, size=(3,2), dtype=np.uint8)
print(f"var: {var}")
print(f"list: {list_}")
res = find_if_in_range(list_, var)
print(res)

Output:

var: 0
list: [[0 6]
 [2 7]
 [7 9]]
True

Hope this helps.

Cheers.