What Is the Correct Format to Write Float Value to File in Python

What is the correct format to write float value to file in Python

the way you are writing to the file looks like you are giving two arguments to write function. So you need to only pass one argument. try converting x1 and x2 into string and then write to the file.

f.write("This is x1 " + str(x1))
f.write("This is x2 " + str(x2))

How do I write a float list of lists to file in Python

m = [[1.1, 2.1, 3.1], [4.1, 5.1, 6.1], [7.1, 8.1, 9.1]]
file.write(str(m))

If you want more control over the format of each value:

def format(value):
    return "%.3f" % value

formatted = [[format(v) for v in r] for r in m]
file.write(str(formatted))

In Python: How can I write floating point numbers in a file using a specified number of figures?

You can do this several ways:

print("%.3f " % my_float_value) # Using formatting for Python2.7

or

print("{0:.3f} ".format(my_float_value)) # Using modern string formatting

or

print(f"{my_float_value:.3f}") # A newer form of string formatting

How to append float in a text file in python?

You have to convert the float to a string first.

employee_file.write(str(salary))

Also, you might want to append a newline, as File.write() does not do that automatically.

employee_file.write(str(salary) + '\n')

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Further, do not open and close files explicitely. It is considered better practice to do that with python's with construct:

num2 = float(input("Enter 2nd num: "))
salary = num1 - num2
with open("employee_salary.txt", "a") as employee_file:
    employee_file.write(str(salary) + '\n')
# No close necessary, the end of the with-paragraph closes the file automatically

Writing floating point numbers to a file in "ab" mode

Try :

with open('report.txt', "ab") as f:
    f.write(b"\n Result Pattern\n")
    f.write(b'%f' %test_accuracy) # you need to add b here.

How to read/write float values from a binary file in python, if the file was created with C

import struct
with open("array.bin","rb") as file:
    numbers = struct.unpack('f'*10, file.read(4*10))
print (numbers)

This should do the job. numbers is a tuple of the 10 values.

Python formatting CSV with string and float and write

You can iterate the result in order to parse only the floats values, and then you can use writer.writerows(row) to write row by row. Take a look here to know the different ways to iterate your results.

On the other hand, you can format floats to two decimals points using the round() function from python.

An example:

>>> # Each of your rows should be something like: 
>>> list = ["string1", "string3", 1.435654, 4.43256]

>>> #Round the floats
>>> parsed_list = [round(x, 2) if i > 1 else x for i, x in enumerate(list)]

>>> print parsed_list
['string1', 'string2', 1.44, 4.43]

Can't output Float values to text file using Python 3

String formatting should help with both of your problems. Here is your example, with some irrelevant parts removed:

ra = [1.5, 2.1, 3.3, 11./7]

outputFile = open('outFile.txt', 'w')
for i in range(4):
    outputFile.write('{} \n'.format(ra[i]))

Notice:

• The output text file is open for text, not binary, w, not wb
• The float variable is formatted by the {} directive inside the string.
• The whitespace and newline are easily included in the format string.

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