Python Typeerror: Not All Arguments Converted During String Formatting

Python can be described as an enforcer of the rules. One of the most important characteristics of Python is that the Python language is that it keeps you on track to ensure your programs function exactly as you intended. There’s a chance that you’ll run into an error that says “not all arguments are converted in the process of formatting strings” when using strings.

In this tutorial we will discuss the error that causes it and the reason why it is a problem. We will walk you through two common scenarios in which this error is brought up to help you fix the issue within your code.

The Issue: typeerror: not all arguments were converted in string formatting

A TypeError is a kind of error which tells us that we’re performing a task which cannot be completed by a particular kind. In this instance, the type error is related to a string.

Python provides a variety of ways to create the strings. This lets you insert values into strings, or to concatenate values until the end of strings.

One of the two popular methods for formatting strings are:

  • Utilizing the % operator (old-style)
  • {Using the Utilizing theoperator using it’s .format() method

When you try to combine each of the syntaxes the error message is signaled.

Example: Mixing String Formatting Rules

Let’s develop a program which determines a 5% increase for a product that is that is sold in the bakery.

We begin by gathering two details from the customer The name of the item and the cost of the item. This is done with the input() statement:

name input = input("Enter what the title of your item is: ") price = input("Enter the price of the product: ")

Next, we calculate cost of the item by multiplying the amount”price” by 1 “price” in 1.05. This is an increase of 5:

increase by round(float(price) * 1.05 2,)

We can round the amount from “increase” by two decimal places by using the round() statement. Then, we make use of the string format to print the updated price of the product on the console:

print("The new price {of for" $. " % name, str(increase))

This code incorporates the values from “name” as well as “increase” to our string. We transform “increase” into the form of a string, which we then incorporate with our existing string. Prior to conversion, “increase” is a floating-point number. Check out our code to check out the results:

Traceback (most recent call in last) File "" 6, line 6 in print("The new price {of for{is is"  name ) str(discount)) Error in TypeError not all arguments were changed during formatting of strings

There is an error on the final part of the code.

The problem is that we mix our syntax for formatting strings. We {used the utilized theand operators . They are utilized for two types of formatting strings.

To address this issue to solve this issue, we can replace the last line of our code by one of the two below lines of code:

print("The new price {of for".format(name, str(increase)) print $. ".format(name, str(increase))) print("The new price for  $%s will be $%s." % (name, str(increase)))

In the first code line, it employs syntax known as the .format() syntax. It replaces the value of {by the values specified in the .format() statement in the order in which they are defined.

Second line employs the traditional formatting technique for strings. The value “%s” are replaced with those enclosed in parenthesis following the “%” operator.

Let’s run the code once more and observe what happens:

Name the item: Babka Enter the price of the product: 2.50 The new price of Babka is $2.62.

Our code was able to successfully add our arguments to our string.

Example: Confusion of the Modulo Operator

Python employs percent sign ( percent) in order to compute modulo number along with string formatting. Modulo numbers are what’s that remains after an equation by a sum.

If you apply the percentage symbol on an unformatted string, it’s used to format it; however, if you apply an % sign with an amount, it will be employed to compute the modulo. Therefore, if a number is presented as a string which you wish to carry out the calculation of a modulo the error will be raised.

Look at an application that determines if the number is unusual or even:

number is input("Please fill in the number: ") mod_calc = number  2 % if mod_calcequals 0: print("This number is even.") alternatively: print("This number is odd.")

Then, we require the user to input an amount. Then, we use the modulo operation to determine the remaining which is returned after “number” has been divided into two.

If the return value of modulo operator greater than zero then the content of the If statement run. If not, the contents that are in our otherwise statement run.

Let’s test our code:

Enter a number: 7 traceback (most recent call made last) in the file "" 2, line 2 2, in mod_calc = number%2 TypeError: Not all arguments were converted in string formatting

Another TypeError. The error is triggered as “number” is an unicode string. Input() input() method returns the string. We must convert “number” into a floating-point or an integer, if we are planning to perform the modulo calculation.

It is possible to convert “number” to a floating by using the floating() method:

mod_calc = float(number) % 2

Let’s run our code once more:

Enter a number: 7. This is not normal.

Our code works!


It is the “not all arguments are converted during formatting of string” error is triggered when Python does not include all arguments in the string format operation. This can happen if you mess up your syntax for formatting strings or when you attempt to do a modulo operation on strings.

Now you’re ready to tackle this most common Python error as you would a expert Software engineer!

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