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In this tutorial, we will learn how to convert python String to int and int to String in python. In our previous tutorial we learned about Python List append function.
If you read our previous tutorials, you may notice that at some time we used this conversion. Actually, this is necessary in many cases. For example, you are reading some data from a file, then it will be in String format and you will have to convert String to an int. Now, we will go straight to the code. If you want to convert a number that is represented in the string to int, you have to use
int() function to do so. See the following example:
num = '123' # string data # print the type print('Type of num is :', type(num)) # convert using int() num = int(num) # print the type again print('Now, type of num is :', type(num))
The output of the following code will be
Type of num is : <class 'str'> Now, type of num is : <class 'int'>
If the string you want to convert into int belongs to different number base other that base 10, you can specify the base for conversion. But remember that the output integer is always in base 10. Another thing you need to remember is that the given base must be in between 2 to 36. See the following example to understand the conversion of string to int with the base argument.
num = '123' # print the original string print('The original string :', num) # considering '123' be in base 10, convert it to base 10 print('Base 10 to base 10:', int(num)) # considering '123' be in base 8, convert it to base 10 print('Base 8 to base 10 :', int(num, base=8)) # considering '123' be in base 6, convert it to base 10 print('Base 6 to base 10 :', int(num, base=6))
The output of the following code will be
While converting from string to int you may get
ValueError exception. This exception occurs if the string you want to convert does not represent any numbers. Suppose, you want to convert a hexadecimal number to an integer. But you did not pass argument base=16 in the int() function. It will raise a
ValueError exception if there is any digit that does not belong to the decimal number system. The following example will illustrate this exception while converting a string to int.
""" Scenario 1: The interpreter will not raise any exception but you get wrong data """ num = '12' # this is a hexadecimal value # the variable is considered as decimal value during conversion print('The value is :', int(num)) # the variable is considered as hexadecimal value during conversion print('Actual value is :', int(num, base=16)) """ Scenario 2: The interpreter will raise ValueError exception """ num = '1e' # this is a hexadecimal value # the variable is considered as hexadecimal value during conversion print('Actual value of \'1e\' is :', int(num, base=16)) # the variable is considered as decimal value during conversion print('The value is :', int(num)) # this will raise exception
The output of the above code will be:
The value is : 12 Actual value is : 18 Actual value of '1e' is : 30 Traceback (most recent call last): File "/home/imtiaz/Desktop/str2int_exception.py", line 22, in print('The value is :', int(num)) # this will raise exception ValueError: invalid literal for int() with base 10: '1e'
Converting an int to string requires no effort or checking. You just use
str() function to do the conversion. See the following example.
hexadecimalValue = 0x1eff print('Type of hexadecimalValue :', type(hexadecimalValue)) hexadecimalValue = str(hexadecimalValue) print('Type of hexadecimalValue now :', type(hexadecimalValue))
The output of the following code will be:
Type of hexadecimalValue : <class 'int'> Type of hexadecimalValue now : <class 'str'>
That’s all about Python convert String to int and int to string conversion. Reference: Python Official Doc
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hellow i have a question this my activity its very defficult😊 here is the output using python write a program that accepts decimal integer and ask the user to what numeric literal conversion is. Test 1 Enter a number: 100 convert to - Type A binary B octal C hex): A In binary: 0b1100100 Test case 2 Enter a number: 31 convert to - Type A binary B octal C hex): C In hexadecimal: 1F thats the output! how to program that output
- Lesther Pontillas
I’m trying to make an if statement that will find whether or not the item is a number in the string, if it is, it will take that number and repeat a function that many times. I’m really confused on how I would make this work
here 123 is an single number this doesn’t work for a = '1 2 3 ’ seperated by spaces how ???
Two minor corrections: (1) You wrote: “But remember that the output integer is always in base 10” The output of int() is an integer, stored in the computer’s native format for numbers, binary. By default, when printing out variables or results of type int, they are printed in decimal (2) You wrote: “Another thing you need to remember is that the given base must be in between 2 to 32.” the correct range is base 2 to base 36 3) A suggestion: The industry standard for decades for base 16 is “hexadecimal” , I have never seen Hexa as an alternative 4) As an alternative to a block of code followed by a block of output, maybe a screen capture of the examples and results as shown in an IDE such as Idle., so that the results are right next to the example statements
- Philip Freidin