Problem –
You want to format a number for output and you want to control the number of digits after decimal or want to add thousand separators or use exponential notations etc.
Solution –
To format a number in python you can use the format function.
In [1]: x = 274.67894
In [2]: # format to 1 decimal place
In [3]: format(x, '0.1f')
Out[3]: '274.7'
In [4]: # format to 2 decimal places
In [5]: format(x, '0.2f')
Out[5]: '274.68'
In [6]: # left justify 10 chars with 1 decimal accuracy
In [7]: format(x, '<10.1f')
Out[7]: '274.7 '
In [8]: # right justify 10 chars with 1 decimal accuracy
In [9]: format(x, '>10.1f')
Out[9]: ' 274.7'
In [10]: # centered
In [11]: format(x, '^10.1f')
Out[11]: ' 274.7 '
In [12]: y = 1000000
In [13]: # include thousand separator
In [14]: format(y, ',')
Out[14]: '1,000,000'
In [15]: # use exponential notation
In [16]: format(y, 'e')
Out[16]: '1.000000e+06'
In [17]: format(y, 'E')
Out[17]: '1.000000E+06'
In [18]: