I/O Print

Python print/print() is very powerful... taking styling from C string formating and adding some of it's own functionality; allowing for deep functionality. Pull up PyDocs and reference Py2 and Py3 print, %, and formatting.

Python 2 Basic:

print "hello"
print 1+1
print 'Hello' + 'world'
print 'Hello' , 'World')

Python 3 Basic:

print("hello")
print(1+1)
print('Hello' + 'World')
print('Hello' , 'World')

% Formatting

% formatting follows C style and is being phased out. It is highly recommend to use .format()… but have practice with both!

​# Basic Positional Formatting
print "%s World!" % "Hello"
'Hello World!'

# Basic Positional Formatting
print "%s %s!" % ("Hello", "World")
'Hello World!'

# Padding 10 left
print '%10s' % ('test',)
'      test'

# Negative Padding 10 right
print '%-10s' % ('test',)
'test          '

# Truncating Long Strings
print '%.5s' % ('what in the world',)
'what '

# Truncating and padding
print '%10.5s' % ('what in the world',)
'     what'

# Numbers
print '%d' % (50,)
50

# Floats
print '%f' % (3.123513423532432)
3.123513

# Padding numbers
print '%4d' % (50,)
  50

# Padding Floating Points
print '%06.2f' % (3.141592653589793,)
003.14

# Name Placeholders
things = {'car': 'BMW E30', 'motorcycle': 'Harley FXDX'}
print 'My fav car %(car)s and motorcycle %(motorcycle)s' % things
'My fav car BMW E30 and motorcycle Harley FXDX'

.format()

Format() is the latest formatting functionality. PEP8 high encourages the use of .format() whenever possible. .format() includes most of the previous functionality with a ton of added functionality as well. Below is just SOME of the built in .format() functionality. Keep in mind, you can create custom functionality with .format(). Take a look at the docs and below and experiment!

​# Basic Positional Formatting
print '{} {}!'.format('Hello', 'World')
'Hello World!'

# Basic Positional Formatting
print "{!s} {!s}".format("Hello", "World")
'Hello World!'

# Actual Positional Formatting
# EXCLUSIVE
print '{1} {0}!'.format('World', 'Hello')
'Hello World!'

# Padding 10 left
print '{:>10}'.format('test')
'      test'

# Negative Padding 10 right
print '{:<10}'.format('test')
'test      '

# Changing Padding Character
# EXCLUSIVE
print '{:_>10}'.format('test')
'______test'

# Center Align
# EXCLUSIVE
print '{:_^10}'.format('test')
'___test___'

# Truncating Long Strings
print '{:.5}'.format('what in the world')
'what '

# Truncating and padding
'{:10.5}'.format('what in the world')
'     what'

# Numbers
print '{:d}'.format(50)
50

# Floats
print '{:f}'.format(3.123513423532432)
3.123513

# Padding numbers
print '{:4d}'.format(50)
  50

# Padding Floating Points
print '{:06.2f}'.format(3.141592653589793)
003.14

# Name Placeholders
things = {'car': 'BMW E30', 'motorcycle': 'Harley FXDX'}
print 'My fav car {car} and motorcycle {motorcycle}'.format(**things)
'My fav car BMW E30 and motorcycle Harley FXDX'

# Keyword Arguments
# EXCLUSIVE
print '{first} {last}'.format(first='Old', last='Gregg')
'Old Gregg'


# Date and Time
# EXCLUSIVE
from datetime import datetime
print '{:%Y-%m-%d %H:%M}'.format(datetime(2017, 10, 17, 10, 45))
2017-10-17 10:45

Lab 3C: Formatting