The Python float function converts a given value into a float. The float function takes an argument that can be a number or string with the decimal point. For example:
flt_num = float(10)
flt_str = float(“10.5”)
Syntax of using float function
Where x argument rules are as follows:
- If x is a string then it should be a decimal number.
- For a string, you may optionally use a ‘+’ or ‘–‘ sign. Using the ‘+’ sign does not affect the result.
- If x is a string and contains leading or trailing spaces, these are removed.
- A string representing NaN (not-a-number) may also be used.
- An int or float number can be used as an argument. In that case, the floating point number with the same value is returned.
An example of converting a string to float
In the example below, we have a decimal number as a string that is used as an argument in the float Python function. The code and result are shown below:
#Python float demos
flt_x = float("43.59")
print("The returned float number:" ,flt_x)
The result:
Using leading and trailing spaces in string example
Now, I used leading and trailing spaces with a decimal number in the string. As mentioned earlier, the spaces should be removed by float function. See the code and output below:
#Python float demos
str_num = " 55.48 "
flt_spaces = float(str_num)
print("Original string:" ,str_num)
print("After float function:" ,flt_spaces)
Output:
You see, the original string shows spaces while as I displayed the value after using the float function, the spaces in left and right are removed.
The example of using int and float
This example shows the returned values after using an int and floating numbers in the float function.
int_num = 35
flt_num = 61.89
print("Int after float function:" ,float(int_num))
print("Float number after:" ,float(flt_num))
The output:
Int after float function: 35.0
Float number after: 61.89
An example of checking if a value is NaN
The example below uses math module and checks if the value is NaN by float function:
import math
print (math.isnan(float('NaN')))
print (math.isnan(25.0))
The result:
True
False
What if an alphabet is used in float function?
A ValueError will be generated if alphabets are given in the float function. Have a look at an example below:
str_flt = "test" print (float(str_flt))
The output:
