Python | Check for float string

One of the most notable breakthrough that Python brought was that the interconversion between the datatypes was done in a very easy manner and hence making it quite powerful. String can be converted to integers easily, but converting a float value is still difficult task. Let’s discuss certain ways in which one can check if string is a float to avoid potential errors.

Method #1 : Using isdigit() + replace()
The combination of above function is used to perform this task and hence. This works in 2 steps, first the point value is erased and the string is joined to form a digit and then is checked. The drawback is that this doesn’t check for potential exponent values that can also form a float number.

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# Python3 code to demonstrate
# Check for float string
# using isdigit() + replace()
  
# initializing string 
test_string = "45.657"
  
# printing original string 
print("The original string : " + str(test_string))
  
# using isdigit() + replace()
# Check for float string
res = test_string.replace('.', '', 1).isdigit()
  
# print result
print("Is string a possible float number ? : " + str(res))

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Output :



The original string : 45.657
Is string a possible float number ? : True

 

Method #2 : Using float() + Exception handling
This task can also be achieved using the float function which tries to convert the string to floating point value, and it’s failure guarantees that it’s not potential float value.

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# Python3 code to demonstrate
# Check for float string
# using float()
  
# initializing string 
test_string = "45.657"
  
# printing original string 
print("The original string : " + str(test_string))
  
# using float()
# Check for float string
try
    float(test_string)
    res = True
except :
    print("Not a float")
    res = False
      
# print result
print("Is string a possible float number ? : " + str(res))

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Output :

The original string : 45.657
Is string a possible float number ? : True


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