In this Python tutorial, we will learn how to format a floating number to a fixed width.
Table Of Contents
Format a floating number to fixed width using % operator
The % operator can be used as a formatting operator. Such that it can be possible to return fixed width from a floating point number. We need to specify the width as an integer (number of decimals) to be returned.
Syntax:
'%.nf'%value
Where n specifies the width and value is the floating point number. It returns a fixed width float point number.
Example 1:
Consider the floating number – 12.456734455 and return 6,8 and 2 decimals separately.
# Consider a float value with 9 decimals
value = 12.456734455
# Get upto 6 decimals
print ('value upto 6 decimals - %.6f' % value)
# Get upto 8 decimals
print ('value upto 8 decimals - %.8f' % value)
# Get upto 2 decimals
print ('value upto 2 decimals - %.2f' % value)
Output:
value upto 6 decimals - 12.456734 value upto 8 decimals - 12.45673445 value upto 2 decimals - 12.46
- We specified width as 6. so it returned only 6 decimals – 12.456734
- We specified width as 8. so it returned only 6 decimals – 12.45673445
- We specified width as 2. so it returned only 6 decimals – 12.45
Example 2:
Consider the 5 floating point numbers in a list and return the result in a fixed width.
# Consider a float values with different decimals in a list
values = [12.456734455,5.6789,9.232345,7.89998,8.00122]
# Get upto 3 decimals
for i in values:
print ('value upto 3 decimals - %.6f'%i)
# Get upto 2 decimals
for i in values:
print ('value upto 2 decimals - %.2f'%i)
Output:
value upto 3 decimals - 12.456734 value upto 3 decimals - 5.678900 value upto 3 decimals - 9.232345 value upto 3 decimals - 7.899980 value upto 3 decimals - 8.001220 value upto 2 decimals - 12.46 value upto 2 decimals - 5.68 value upto 2 decimals - 9.23 value upto 2 decimals - 7.90 value upto 2 decimals - 8.00
We returned floating numbers in a list with widths of 3 and 2 separately.
Format a floating number to fixed width using round()
The round() function is used to round the given float value to a specified width. It rounds to the nearest value.
Syntax:
round(value,width)
It returns a fixed width float point number.
Parameters:
1. value specifies float value
2. width specifies the number of decimals to be returned.
Example:
In this example, we will round the value – 12.456734455 to 6,8 and 2 separately.
# Consider a float value with 9 decimals
value = 12.456734455
# Get upto 6 decimals
print ("value upto 6 decimals",round(value,6))
# Get upto 8 decimals
print ("value upto 8 decimals",round(value,8))
# Get upto 2 decimals
print ("value upto 2 decimals",round(value,2))
Output:
value upto 6 decimals 12.456734 value upto 8 decimals 12.45673445 value upto 2 decimals 12.46
- 12.456734455 is rounded to 12.456734 by specifying a width as 6.
- 12.456734455 is rounded to 12.45673445 by specifying a width as 8.
- 12.456734455 is rounded to the nearest value – 12.46 by specifying a width as 2.
Format a floating number to fixed width using format()
The format() is used to round the given float value to a specified width. It rounds to the nearest value.
Syntax:
"{:.nf}".format(value)
Where n specifies the width and value is the floating point number.
Example:1
In this example, we will format the value – 12.456734455 to 4,8, and 2 separately.
# Consider a float value with 9 decimals
value = 12.456734455
# Get upto 4 decimals
print ("value upto 6 decimals - {:.4f}".format(value))
# Get upto 8 decimals
print ("value upto 8 decimals - {:.8f}".format(value))
# Get upto 2 decimals
print ("value upto 2 decimals - {:.2f}".format(value))
Output:
value upto 6 decimals - 12.4567 value upto 8 decimals - 12.45673445 value upto 2 decimals - 12.46
- 12.456734455 is formatted to 12.4567 by specifying a width as 4.
- 12.456734455 is formatted to 12.45673445 by specifying a width as 8.
- 12.456734455 is formatted to the nearest value – 12.46 by specifying a width as 2.
Example:2
In this example, we will format the value – 89.01123443535 to 6,8 and 2 separately.
# Consider a float value with 11 decimals
value = 89.01123443535
# Get upto 6 decimals
print ("value upto 6 decimals - {:.6f}".format(value))
# Get upto 8 decimals
print ("value upto 8 decimals - {:.8f}".format(value))
# Get upto 2 decimals
print ("value upto 2 decimals - {:.2f}".format(value))
Output:
value upto 6 decimals - 89.011234 value upto 8 decimals - 89.01123444 value upto 2 decimals - 89.01
Summary
In this Python tutorial, we have seen how to format a floating point number to a fixed width using round(), format and % operator. The round() and format() methods operates with the same functionality. Thanks.