How do you convert a string to an integer or a float in python?
It's good that you ask to do these separately. If you're mixing them, you may be setting yourself up for problems later. The simple answer is:
Other conversions, ints to and from strings and literals:Conversions from various bases, and you should know the base in advance (10 is the default). Note you can prefix them with what Python expects for its literals (see below) or remove the prefix:
If you don't know the base in advance, but you do know they will have the correct prefix, Python can infer this for you if you pass
Non-Decimal (i.e. Integer) Literals from other BasesIf your motivation is to have your own code clearly represent hard-coded specific values, however, you may not need to convert from the bases - you can let Python do it for you automatically with the correct syntax. You can use the apropos prefixes to get automatic conversion to integers with the following literals. These are valid for Python 2 and 3: Binary, prefix
Octal, prefix
Hexadecimal, prefix
This can be useful when describing binary flags, file permissions in code, or hex values for colors - for example, note no quotes:
Making ambiguous Python 2 octals compatible with Python 3If you see an integer that starts with a 0, in Python 2, this is (deprecated) octal syntax.
It is bad because it looks like the value should be
Convert your Python 2 octals to octals that work in both 2 and 3 with the In this example, you will learn to parse a string to a float or int. To understand this example, you should have the knowledge of the following Python programming topics:
Example 1: Parse string into integer
Output
Note: The string must be a numeral value. Example 2: Parse string into float
Output
Example 3: A string float numeral into integer
Output
If the string is a float numeral, you can convert it into a float type using IntroductionIn Python, data types are used to classify one particular type of data, determining the values that you can assign to the type and the operations you can perform on it. When programming, there are times we need to convert values between types in order to manipulate values in a different way. For example, we may need to concatenate numeric values with strings, or represent decimal places in numbers that were initialized as integer values. This tutorial will guide you through converting numbers, strings, tuples and lists, as well as provide examples to help familiarize yourself with different use cases. PrerequisitesYou should have Python 3 installed and a programming environment set up on your computer or server. If you don’t have a programming environment set up, you can refer to the installation and setup guides for a local programming environment or for a programming environment on your server appropriate for your operating system (Ubuntu, CentOS, Debian, etc.) Converting Number TypesIn Python, there are two number data types: integers and floating-point numbers or floats. Sometimes you are working on someone else’s code and will need to convert an integer to a float or vice versa, or you may find that you have been using an integer when what you really need is a float. Python has built-in methods to allow you to easily convert integers to floats and floats to integers. Converting Integers to FloatsPython’s method Info: To follow along with the example code in this tutorial, open a Python interactive shell on your local system by running the
In this case, You can also use this with a variable. Let’s declare
By using the Converting Floats to IntegersPython also has a built-in function to convert floats to integers: The
In this case, You can also use this with variables. Let’s declare
When converting floats to integers with the Numbers Converted Through DivisionIn Python 3, relevant quotients are converted from integers to floats when doing division though they are not in Python 2. That is, when you divide 5 by 2, in Python 3 you will get a float for an answer (2.5):
In Python 2, since you were dealing with two integers, you would receive an integer back as your answer, instead: Converting with StringsA string is a sequence of one or more characters (letters, numbers, symbols). Strings are a common form of data in computer programs, and we may need to convert strings to numbers or numbers to strings fairly often, especially when we are taking in user-generated data. Converting Numbers to StringsWe can convert numbers to strings through using the Let’s first look at converting integers. To convert the integer
When running
The quotes around the number 12 signify that the number is no longer an integer but is now a string value. With variables we can begin to see how practical it can be to convert integers to strings. Let’s say we want to keep track of a user’s daily programming progress and are inputting how many lines of code they write at a time. We would like to show this feedback to the user and will be printing out string and integer values at the same time:
When we run this code, we receive the following error:
We’re not able to concatenate strings and integers in Python, so we’ll have to convert the variable
Now, when we run the code, we receive the following output that congratulates our user on their progress:
If we are looking to convert a float to a string rather than an integer to a string, we follow the same steps and format. When we pass a float into the
We can test to make sure it’s right by concatenating with a string:
We can be sure our float was properly converted to a string because the concatenation was performed without error. Converting Strings to NumbersStrings can be converted to numbers by using the If your string does not have decimal places, you’ll most likely want to convert it to an integer by using the Let’s use the example of the user Sammy keeping track of lines of code written each day. We may want to manipulate those values with math to provide more interesting feedback for the user, but those values are currently stored in strings:
Because the two numeric values were stored in strings, we received an error. The operand Let’s modify the code to include the
The variable We can also convert the numbers in the example above to float values by using the The user Sammy is earning points in decimal values
In this case, using the We’ll want to convert these strings to floats prior to performing any math with the
Now that we have converted the two strings to floats, we receive the anticipated result that adds If we try to convert a string value with decimal places to an integer, we’ll receive an error:
If we pass a decimal value in a string to the Converting strings to numbers enables us to quickly modify the data type we are working with so that we can perform operations on numeric values that were originally cast as strings. Converting to Tuples and ListsYou can use the methods
Converting to TuplesLet’s start with converting a list to a tuple. Converting a list to a tuple, because it’s an immutable data type, can allow substantial optimization to the programs that we create. When we use the method
We see that a tuple is printed out in the output, as the items are now contained within parentheses rather than square brackets. Let’s use
Again, we see that the list value is changed to a tuple value, indicated by the parentheses. We can convert any iterable type to a tuple, including strings:
Because we can iterate through strings, we can convert them to tuples with the
While it is possible to convert the integer to a string and then convert to a tuple, as in Converting to ListsConverting values, especially tuples, to lists can be useful when you need to have a mutable version of that value. We’ll use the
The square brackets signal that a list has been returned from the original tuple value that was passed through the To make the code more readable, we can remove one of the pairs of parentheses by using a variable:
If we print Just like tuples, strings can be converted to lists:
Here the string ConclusionThis Python tutorial demonstrated how to convert several of the important native data types to other data types, primarily through built-in methods. Being able to convert data types in Python provides you with extra flexibility when writing your programs. How do I convert a string to a float in Python?We can convert a string to float in Python using the float() function. This is a built-in function used to convert an object to a floating point number. Internally, the float() function calls specified object __float__() function.
Can you convert string to int or float?Strings can be converted to numbers by using the int() and float() methods.
How do you convert string to integer in Python?To convert, or cast, a string to an integer in Python, you use the int() built-in function. The function takes in as a parameter the initial string you want to convert, and returns the integer equivalent of the value you passed. The general syntax looks something like this: int("str") .
How do you change a datatype to a float in Python?To convert the integer to float, use the float() function in Python. Similarly, if you want to convert a float to an integer, you can use the int() function.
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