Determining If a Variable Is Within Range

Check if a value is within a range of numbers

You're asking a question about numeric comparisons, so regular expressions really have nothing to do with the issue. You don't need "multiple if" statements to do it, either:

if (x >= 0.001 && x <= 0.009) {
  // something
}

You could write yourself a "between()" function:

function between(x, min, max) {
  return x >= min && x <= max;
}
// ...
if (between(x, 0.001, 0.009)) {
  // something
}

How to elegantly check if a number is within a range?

There are a lot of options:

int x = 30;
if (Enumerable.Range(1,100).Contains(x))  //true

And indeed basic if more elegantly can be written with reversing order in the first check:

if (1 <= x && x <= 100)   //true

Also, check out this SO post for regex options.

Notes:

LINQ solution is strictly for style points - since Contains iterates over all items its complexity is O(range_size) and not O(1) normally expected from a range check.

More generic version for other ranges (notice that second argument is count, not end):
```
if (Enumerable.Range(start, end - start + 1).Contains(x)
```
There is temptation to write if solution without && like 1 <= x <= 100 - that look really elegant, but in C# leads to a syntax error "Operator '<=' cannot be applied to operands of type 'bool' and 'int'"

How do I determine if a value is within a range?

It is because you have declared i variable as int and you are taking input as string so when it is checking condition it is getting null value in i variable and not able to enter if block check below code

    #include <stdio.h>

    int main(){

      int i;
        printf("Value to check Interval \n");
        scanf("%d",&i);

      if (i>4 && i<6){
        printf("%d Value is in first interval\n", i);
      }
    }

try compiling your code without if condition i variable will return a null value

Check to see if a value is within a range?

Assuming that the values of ID are unique:

DT[, list(OK = 1 %in% seq(time.s, time.e)), by = ID]

giving;

   ID    OK
1:  1  TRUE
2:  2  TRUE
3:  3 FALSE
4:  4 FALSE

Determine whether integer is between two other integers

if 10000 <= number <= 30000:
    pass

For details, see the docs.

How to check if a number is within a range in shell

If you are using Bash, you are better off using the arithmetic expression, ((...)) for readability and flexibility:

if ((number >= 2 && number <= 5)); then
  # your code
fi

To read in a loop until a valid number is entered:

#!/bin/bash

while :; do
  read -p "Enter a number between 2 and 5: " number
  [[ $number =~ ^[0-9]+$ ]] || { echo "Enter a valid number"; continue; }
  if ((number >= 2 && number <= 5)); then
    echo "valid number"
    break
  else
    echo "number out of range, try again"
  fi
done

((number >= 2 && number <= 5)) can also be written as ((2 <= number <= 5)).

How to check if a number falls in a given range

This the simplest way:

    $check = 0;
    $nextCheck = $check+1001;
    while ($check < 100001) {
    If ($user_id > $check && $user_id < $nextCheck) {
      // Code ...
      break;
    } else {
       $check+=1000;
       $nextCheck+=1000;
    }
    }

How to test if variable is in within a certain range?

Sure, a value is not in a range if it is less than the lower bound or greater than the upper bound.

if ( var < x || var > y )

You might find a list of operator in C and C++ useful.