How to get the sign of an integer in Python?

Introduction

Python Integers are one of the major data types used in almost all major mathematical and logical operations. In Python, an integer is zero, a positive or negative integer, has no decimal part, and has infinite precision. They can be represented in binary, octal and hexadecimal values. In this article, we will learn how to get the sign of an integer.

usage instructions

• Use simple mathematical comparison with zero

• Use the copysign() function of the math module

• Use numpy.sign() function

• Use the abs() function to create a method

Method 1: Using mathematical comparison with zero

We can use the basic mathematical definitions of positive and negative numbers to find the sign of a given integer. We use a basic if-else construct to determine the sign of a number.

grammar

if number>0 return 1
else if number<0 return -1
else return 0

In this method, we use a cascading if-else-if structure to create a decision point at the zero point of the integer number line. If the number entered by the user is greater than zero, the program returns 1, if it is less than zero, the program returns -1, and if it is zero, the program returns zero as the answer.

algorithm

Step 1 - Get the integer entered by the user to determine the sign

Step 2 - Create an "if" with the initial condition that if the input number is greater than zero, the function returns 1

Step 3 - Create a cascading "else-if" condition that returns -1 if the input number is less than zero

Step 4 - Create a final "else" condition where if the input number is zero, the function returns zero

Example

def solution(number):
   if (number>0):
      return 1
   elif (number<0):
      return -1
   else:
      return 0

val =-2
sol = solution(val)
print(sol) 

Output

-1

Method 2: Use the copysign() function of the Math module

The copysign() function in the math module returns the value of the first argument and the sign of the second argument. Therefore, we use 1 instead of the first argument to find the sign of the input integer as the second argument. This function can handle integers, floating point numbers, and positive and negative nan values.

grammar

return copysign(1,number)

To do this, we need to call the copysign function. As parameters we need to pass two numbers and the function returns the magnitude of the first number and the sign of the second number as a single number.

algorithm

Step 1 - ImportMathModule

Step 2 - Get the input integer whose sign is to be determined from the user

Step 3 - Pass the integer as the second parameter in the copysign() function according to the given syntax

Example

import math
def solution(number):
   return int(math.copysign(1,number))
val = -2
sol = solution(val)
print(sol) 

Output

-1

Method 3: Use numpy.sign() function

The numpy module provides the sign() function, which can be used to determine the sign of an integer. This is useful because Python's math library does not have any sign() function by default. It can be used on an entire integer array to display symbols element by element.

grammar

numpy.sign(array [], out)

The syntax is very simple, it calls the sign function and passes two parameters. Only the first parameter is mandatory, the second parameter is optional. The first parameter is passed the array of elements and the second parameter is the output array to be placed with the results.

algorithm

Step 1 - Import the numpy module

Step 2 - Get the input element in the array whose symbol needs to be determined

Step 3 - Call the sign() function and pass the array containing the target element

Step 4 - Display the output value, i.e. the sign of the integer

Example

import numpy as user #importing numpy
array=[25, -25, 0] #input array
print("input array : ", array) #input array with elements
print("Check sign of array : ", user.sign(array)) #signs of elements

Output

input array: [25 -25 0]
Check sign of array: [1 -1 0]

Method 4: Use the abs() function to create a method

We can use the abs() function to define a symbol function that returns an integer symbol. The abs() function returns the absolute value of a number.

grammar

return x/abs(x) 

Here we divide the integer by its absolute value to find the sign of the integer. When we divide two integers here, the function returns a floating point value, but it works on integers.

algorithm

Step 1 - Define a function

Step 2 - Pass the number to the function whose sign you want to determine as argument

Step 3 - Create an "if-else" structure to check if the input integer is zero

Step 4 - Display the output value by dividing the integer by its absolute value

Example

def int_sign(x):
   if (x==0): return 0
   else: return x/abs(x)
num=-2
print(int_sign(num))    

Output

-1.0

in conclusion

In this article, we discussed some methods of finding integer symbols provided by the user or set in the program. This article was generally written with Python in mind, but similar methods can be used in different programming languages.

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