--- title: Converting Integer to String in Python --- ## Converting Integer to String in Python Unlike many other languages out there, Python does not implicitly typecast integers (or floats) to strings when concatenating with strings. Fortunately, Python has a handy built-in function `str()` which will convert the argument passed in to a string format. #### The Wrong Way Programmers coming from other languages may attempt to do the following string concatenation which produces an error: ```py age = 18 string = "Hello, I am " + age + " years old" ``` Run code on repl.it The error that shows up is ``` Traceback (most recent call last): File "python", line 3, in TypeError: must be str, not int ``` `TypeError: must be str, not int` indicates that the integer must first be converted to a string to be concatenated. #### The Correct Way Simple concatenation example: ```py age = 18 print("Hello, I am " + str(age) + " years old") # Output # Hello, I am 18 years old ``` Run code on repl.it Print `1 2 3 4 5 6 7 8 9 10` using a single string ```py result = "" for i in range(1, 11): result += str(i) + " " print(result) # Output # 1 2 3 4 5 6 7 8 9 10 ``` Run code on repl.it #### Line by Line explanation of the above code 1. First, a variable 'result' is assigned to an empty string. 2. For loop is being used to iterate over a list of numbers. 3. This list of numbers is generated using the range function. 4. So range(1,11) is going to generate a list of numbers from 1 to 10. 5. On each for loop iteration, the 'i' variable is going to take up values from 1 to 10. 6. On first iteration when the variable i=1, then the variable [result=result+str(i)+"(space character)"],str(i) converts the 'i' which is an integer value to a string value. 7. Since i=1, on the first iteration finally result=1. 8. And the same process goes on until i=10 and finally after the last iteration result=1 2 3 4 5 6 7 8 9 10. 9. Therefore when we finally print the result after the for loop the output on the console is '1 2 3 4 5 6 7 8 9 10'. #### More Information: Official Python documentation for `str()`