Valueerror: could not convert string to float: How to solve it in Python

Until now, Python has always been highly appreciated by developers as well as programmers for its easy-to-use. Of course, this programming language can also cause several unnecessary errors if you don’t work with it carefully. And, one of the most common errors people face most is Python valueerror: could not convert string to float. However, this error can be avoided effortlessly so you don’t need to worry. So, how can we solve Valueerror could not convert string to float python in the most simple and quick way? ArrowHiTech will instruct you in the following article. Let’s explore right away. 

What does Valueerror in Python mean?

Valueerror could not convert string to float
Python programming language

When working with a programming language like Python, you must take note that a value in Python is the data that is held within a given object. If you attempt to assign a value, you will surely have an issue with the content of the object. Then, there will be a Valueerror. Now, let’s take a look at the following example:

print(int(‘xy’))

As a result, you will get the output like:

Traceback (most recent call last):

File “D:/PycharmProjects/PythonErrors/rough.py”, line 1, in

print(int(‘xy’))

ValueError: invalid literal for int() with base 10: ‘xy’

What is Python valueerror: could not convert string to float? 

As you may know, float() is a Python function for converting a string to a floating-point value.

Then, if you need to execute a mathematical operation on a value, this approach is really an ideal option for you. Also, you can’t do math on a string, but you can with a floating-point number. 

Valueerror could not convert string to float
Python language

What’s more, only strings that look like floats can be converted with the float() function. This is the reason why these values below can’t be converted:

  • There are spaces in a value.
  • A comma appears in a value.
  • Non-special characters are present in a value (for example, “inf” is a special character, while “fd” is not).

After that, if you don’t follow any of the three criteria above, you’ll get the “Python valueerror: could not convert string to float” error. This is because this programming language can only transform a value to a float in case it is formatted in a specific way.

In order to help you understand further about this Valueerror: could not convert string to float, we will show through some instances below. 

Examples of Python valueerror: could not convert string to float

Coming to the first example about developing a program that converts US Dollars (USD) to British Pounds Sterling (GBP).

To begin, users have to enter the dollar amount they wish to convert to pounds:

dollar_value = float(input(“Enter the value you want to convert to GBP: “))

In particular, to perform a mathematical calculation using the value in the future, we transform the value that a user enters into a floating point number.

python programming language
Python programming languae

The next step is placing the exchange rate for USD to GBP with the current rate is 1 USD is worth 0.76 GBP. 

exchange_rate = 0.76

Then, we are able to compute how much our USD is worth in GBP thanks to using these two values. To achieve this goal, let’s multiply “dollar value” by “exchange rate” by following codes below:

final_value = dollar_value * exchange_rate

print(“{} USD is equal to {} GBP”.format(dollar_value, final_value))

Moreover, we created a message using a.format() statement that tells the user how much their USD is worth in GBP. Then, you should have a glance at the following code to see what’s its result:

Enter the value you want to convert to GBP: 23

23.0 USD is equal to 17.48 GBP

As soon as you apply our instructions above successfully, you can continue by adding a number that isn’t structured appropriately. Now, let’s check the output:

Enter the value you want to convert to GBP: 2,300

Traceback (most recent call last):

  File “main.py”, line 1, in <module>

dollar_value = float(input(“Enter the value you want to convert to GBP: “))

Python valueerror: could not convert string to float: ‘2,300’

Finally, it is the main reason to cause Valueerror could not convert string to float python

What is the best way to solve Python valueerror: could not convert string to float?

When we use a valid floating-point value in our software, it will work. In addition, we inserted a comma when trying to insert a figure in the thousands (2,300). As a result, our floating point number is no longer valid. So, how can we solve this problem?

Valueerror could not convert string to float
Python valueerror: could not convert string to float

 Let’s refer to the following solution that applies a “try…except” block: 

try:

dollar_value = float(input(“Enter the value you want to convert to GBP: “))

exchange_rate = 0.76

final_value = dollar_value * exchange_rate

print(“{} USD is equal to {} GBP”.format(dollar_value, final_value))

except:

print(“Please insert a valid number. Currencies cannot contain commas, spaces, or characters.”)

As you probably see, our program will attempt to execute the code included in the “try” block. However, in case it fails, the “except” block will be executed. 

Insert an invalid floating point value

Then, we insert an invalid floating point value into our code and see how it runs:

Enter the value you want to convert to GBP: 2,300

Please insert a valid number. Currencies cannot contain commas, spaces, or characters.

Also, what’s about executing our code with a valid value? You can easily examine the codes below:

Enter the value you want to convert to GBP: 23

23.0 USD is equal to 17.48 GBP

how to avoid Valueerror
Way to solve Valueerror: could not convert string to float

Finally, you can see the Python valueerror: could not convert string to float is extracted successfully in both circumstances. Specifically, the contents of our “unless” block were executed in the first scenario, when we introduced an erroneous value into our program. In the second scenario, our algorithm determined the GBP equivalent of 23 USD.

The final line

In short, if you try to convert a string that isn’t formatted as a floating point number to a float, you will get the “Python valueerror: could not convert string to float” error. This error can be removed by including a handler that ensures your function does not continue to run if the user enters an invalid value. Not only that, using additional input validation before transforming a number to a float() is also the best solution. So, when working with Python, you should be careful to avoid several unexpected errors. 

All in all, ArrowHiTech hopes this article is beneficial for you, then you will master the Python language in the shortest time. Not only Python, but also any other programming language, during the working process, you can easily get hard issues. If you can’t resolve it yourself, let’s ask ArrowHiTech for help and your problems will be removed immediately. 

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