Answer: We have Python in-built functions like float() and int() to parse the string to float or int.
In Python, there is an “implicit type conversion” thereby Python automatically converts the data types to expressions during an operation. However, “explicit type conversion” includes float, int, and boolean conversion. To understand this topic, we need to know about in-detail usage of Python data types.
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Methods to Parse a String to a Float or Int in Python
Python provides various built-in functions to convert a string to a float or int value. Following are some of these methods explained with examples:
Method 1: Parsing String to Int using int() Datatype in Python
We can convert the string to int using the Python built-in datatype int().
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Note: Using strip() datatype we can parse the string to int by removing the spaces that are present in the string.
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Method 2: Parsing String to float using float() Datatype in Python
Using the Python built-in datatype float() we convert the string to float. This built-in function is used to convert an object to a floating point number.
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Note: We can also pass the large number without using a long() datatype. However, we cannot parse the string with multiple decimal points because it throws the invalid format as an error.
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Method 3: Parsing a String with Scientific Notation to Float in Python
In scientific notation, the numbers are expressed as a coefficient multiplied by 10 raised to some power, while converting the number which is represented in short and exponential form to its decimal form.
For example, the string “3.45e4” represents the number 3.45* 10^4, which is equal to 34500.0
Here, “3.45e4” is represented as 3.45 * 10^4, where 10^4 means 10 raised to the power of 4, which is equal to 10000. Therefore 3.45 * 10000 =34500.0
Note: E or e is used as the scientific notation indicator, and both lowercase and uppercase work the same way. The representation for the positive exponent is “e” which indicates multiplication by base 10, while a negative exponent is “e-” which indicates the multiplication by base 10 raised to negative power.
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Method 4: Parsing a String with Numpy to Float in Python
Parsing a string to a float in NumPy is typically done using the numpy.float32 or numpy.float64 types. NumPy provides useful functions especially when dealing with arrays or large datasets.
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In this example, the string “12.34” is converted to a float(numpy.float64) type.
Method 5: Parsing a String with a Decimal to Float in Python
You can directly convert the string to a float using Python’s built-in float() function. While the decimal type offers high precision for decimal numbers, allowing it to handle large values and provide greater accuracy than the built-in float() type.
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Converting the Float to a String in Python
Floats are used for calculations, while strings are meant for text generation. Converting a float to a string is useful for performing math operations and formatting desired outputs. For conversion, we use a built-in Python datatype str().
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Use decimal() when exact decimal representation is needed
Conclusion
Parsing strings to integers or floats in Python is essential for performing arithmetic operations and handling user input. Using built-in functions like int() and float() allows for easy conversions. Handling spaces, large numbers, scientific notation, numpy, and decimal methods is important for accurate parsing. Additionally, converting floats to strings using str() is useful for displaying results. Proper type conversion prevents errors and ensures smooth data processing in Python programs.