Printing variables using formatted output

Python provides a print function that displays the value of a variable. For example,

>>> freq = 22.0/7.0
>>> x = 7.234
>>> print 'Vibration frequency = ', freq
Vibration frequency =  3.14285714286
>>> print 'Vibration frequency = ', freq, 'Displacement =\
... ', x
Vibration frequency =  3.14285714286 Displacement = 7.234

The string modulus operator % allows you to format your output. The %s operator in the following example converts the variables to strings.

>>> print 'Vibration frequency = %s Displacement =\
... %s' % (freq, x)
Vibration frequency = 3.14285714286 Displacement = 7.234

The %f operator specifies floating point notation and indicates the total number of characters to print and the number of decimal places.

>>> print 'Vibration frequency = %6.2f Displacement =\
... %6.2f' % (freq, x)
Vibration frequency =   3.14 Displacement =   7.23

The %E operator specifies scientific notation and indicates the number of decimal places.

>>> print 'Vibration frequency = %.6E Displacement =\
... %.2E' % (freq, x)
Vibration frequency = 3.142857E+00 Displacement = 7.23E+00

The following list includes some additional useful printing operators.

The + flag indicates that a number should include a sign.
The \n escape sequence inserts a new line.
The \t escape sequence inserts a tab character.

For example,

>>> print 'Vibration frequency = %+.6E\nDisplacement =\
... %+.2E' % (freq, x)
Vibration frequency = +3.142857E+00
Displacement = +7.23E+00