![\"Python](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2018\/09\/Python-pprint-01.jpg\")
<\/a>Python pprint Module – Python Data Pretty Printer<\/p><\/div>\n
What is Python Pretty Print?<\/span><\/h3>\nThe pprint module lets us <\/span>pretty-print <\/span><\/i>arbitrary data structures in Python to make them prettier, well-formatted, and more readable. What it gives us is in a form we can use as input to the interpreter. <\/span><\/p>\nThis is just the kind of thing for aesthetics, and it keeps the output on a single line wherever possible. And when on multiple lines, it indents it.<\/span><\/p>\nKey features of pretty print in Python:<\/strong><\/p>\n\n- Automatic formatting:<\/strong> If the limit is exceeded, the object is broken into multiple lines and maintains visual alignment.<\/li>\n
- Sorted dictionaries:<\/strong> To make sure that there is consistency in the output, the dictionary keys are sorted in alphabetical order.<\/li>\n
- No infinite loops:<\/strong> If a list gets stuck in a loop, then the pprint will recognise the loop and print < Recursion on\u2026.> so you can identify where it repeats.<\/li>\n
- East customisation:<\/strong> You can change the way your data looks by setting the indent, width and depth.<\/li>\n<\/ul>\n
Let\u2019s import it:<\/span><\/p>\n>>> from pprint import pprint<\/pre>\nBasically, this module has the following classes:<\/span><\/p>\nclass pprint.PrettyPrinter(indent=1, width=80, depth=None, stream=None, *, compact=False)<\/b><\/p>\n
This constructs a PrettyPrinter instance for us. Let\u2019s talk about its parameters:<\/span><\/p>\n\n- indent<\/span> gives us the amount of indentation for each recursive level<\/span><\/i><\/li>\n
- width<\/span> gives us the desired output width<\/span><\/i><\/li>\n
- depth<\/span> gives us the number of levels to print<\/span><\/i><\/li>\n
- Stream<\/span> lets us set an output stream<\/span><\/i><\/li>\n
- Compact<\/span> lets us fit as many items within the width as we can on each line of output<\/span><\/li>\n<\/ul>\n
Now, let\u2019s try an example without pprint. Let\u2019s take a list to work with:<\/span><\/p>\n>>> data=[(1,{'a':'A','b':'B','c':'C','d':'D'}),(2,{'e':'E','f':'F','g':'G','h':'H','i':'I','j':'J','k':'K','l':'L'}),(3,['m','n']),(4,['o','p','q','r','s','t','u','v','w']),(5,['x','y','z']),]\r\n>>> print(data)<\/pre>\nOutput<\/strong><\/p>\n[(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}), (2, {‘e’: ‘E’, ‘f’: ‘F’, ‘g’: ‘G’, ‘h’: ‘H’, ‘i’: ‘I’, ‘j’: ‘J’, ‘k’: ‘K’, ‘l’: ‘L’}), (3, [‘m’, ‘n’]), (4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]), (5, [‘x’, ‘y’, ‘z’])]<\/div>\nPython pprint Example<\/h3>\n
So, let\u2019s try printing this with pprint instead.<\/span><\/p>\n>>> pprint(data)<\/pre>\nOutput<\/strong><\/p>\n\n[(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}),(2,<\/p>\n
{‘e’: ‘E’,<\/p>\n
‘f’: ‘F’,<\/p>\n
‘g’: ‘G’,<\/p>\n
‘h’: ‘H’,<\/p>\n
‘i’: ‘I’,<\/p>\n
‘j’: ‘J’,<\/p>\n
‘k’: ‘K’,<\/p>\n
‘l’: ‘L’}),<\/p>\n
(3, [‘m’, ‘n’]),<\/p>\n
(4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n
(5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n
So, what does Python pprint do? It formats an object and writes it to the data stream we pass to it as an argument. By default, this is sys.stdout.<\/span><\/p>\nPython pprint Formatting<\/h3>\n
We can format a data structure without having to write it to a stream. To do this, we use pformat() to build a string representation, and possible use cases include logging.<\/span><\/p>\n>>> import logging\r\n>>> from pprint import pformat\r\n>>> logging.basicConfig(\r\n level=logging.DEBUG,\r\n format='%(levelname)-8s %(message)s',)\r\n>>> logging.debug('Logging pformatted data')<\/pre>\nDEBUG \u00a0\u00a0\u00a0Logging pformatted data<\/strong><\/p>\n>>> formatted=pformat(data)<\/pre>\nSo, we can print or log this string independently:<\/span><\/p>\n>>> for line in formatted.splitlines():\r\n logging.debug(line.rstrip())<\/pre>\nOutput<\/strong><\/p>\n\nDEBUG \u00a0\u00a0\u00a0[(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}),DEBUG \u00a0\u00a0\u00a0\u00a0(2,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0{‘e’: ‘E’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘f’: ‘F’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘g’: ‘G’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘h’: ‘H’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘i’: ‘I’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘j’: ‘J’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘k’: ‘K’,<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘l’: ‘L’}),<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0(3, [‘m’, ‘n’]),<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0(4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n
DEBUG \u00a0\u00a0\u00a0\u00a0(5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n
Pretty-Printing Our Own Classes in Python<\/h3>\n
Last, we talked about the repr() built-in function in Python. In that, we observed the __repr__() method. <\/span><\/p>\nToday, let\u2019s see how we can make pprint work with our own classes by making use of the __repr__() method.<\/span><\/p>\n>>> class Color:\r\n def __init__(self,name,hex_value):\r\n self.name=name\r\n self.hex_value=hex_value\r\n def __repr__(self):\r\n return(\r\n 'I am '+self.name+' and you can find me at '+self.hex_value)\r\n>>> colors=[Color('salmon','#FA8072'),Color('olive','#808000'),Color('purple','#800080')]\r\n>>> print(colors)<\/pre>\nOutput<\/strong><\/p>\n[I am salmon and you can find me at #FA8072, I am olive and you can find me at #808000, I am purple and you can find me at #800080]<\/div>\nNow see what Python pprint does to this:<\/span><\/p>\n>>> pprint(colors)<\/pre>\nOutput<\/strong><\/p>\n\n[I am salmon and you can find me at #FA8072,I am olive and you can find me at #808000,<\/p>\n
I am purple and you can find me at #800080]<\/p>\n<\/div>\n
Python Pprint with Recursive Data Structures<\/h3>\n
Let\u2019s create a list and append it to its end. This makes for a recursive list.<\/span><\/p>\n>>> from pprint import pprint\r\n>>> mylist=[1,2,'c','d']\r\n>>> mylist.append(mylist)\r\n>>> id(mylist)<\/pre>\nOutput<\/strong><\/p>\n45553504<\/div>\n>>> pprint(mylist)<\/pre>\nOutput<\/strong><\/p>\n[1, 2, ‘c’, ‘d’, <Recursion on list with id=45553504>]<\/div>\n#The recursive reference<\/span><\/p>\n>>> mylist #Pay attention<\/pre>\nOutput<\/strong><\/p>\n[1, 2, ‘c’, ‘d’, […]]<\/div>\n\n- Controlling Depth-<\/span><\/li>\n<\/ul>\n
To control how far the Python pretty printer recurses down a nested structure, we can use the <\/span>depth <\/span><\/i>argument:<\/span><\/p>\n>>> pprint(data,depth=1)<\/pre>\nOutput<\/strong><\/p>\n[(…), (…), (…), (…), (…)]<\/div>\n>>> pprint(data,depth=2)<\/pre>\nOutput<\/strong><\/p>\n[(1, {…}), (2, {…}), (3, […]), (4, […]), (5, […])]<\/div>\n>>> pprint(data,depth=3)<\/pre>\nOutput<\/strong><\/p>\n[(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}),
\n\u00a0 \u00a0(2,<\/span>{‘e’: ‘E’,’f’: ‘F’,’g’: ‘G’,’h’: ‘H’,<\/p>\n‘i’: ‘I’,<\/p>\n
‘j’: ‘J’,<\/p>\n
‘k’: ‘K’,<\/p>\n
‘l’: ‘L’}),<\/p>\n
(3, [‘m’, ‘n’]),<\/p>\n
(4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n
(5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n
Here, the ellipses denote the levels it excludes from the output.<\/span><\/p>\nDeciding Output Width<\/h3>\n
We can decide the width for the output- this is the number of columns. The default is 80, but we can change that with <\/span>width<\/span><\/i>.<\/span><\/p>\n>>> mylist=[1,2,'c','d']\r\n>>> pprint(mylist)<\/pre>\nOutput<\/strong><\/p>\n[1, 2, ‘c’, ‘d’]<\/div>\n>>> pprint(mylist,width=-1)<\/pre>\nOutput<\/strong><\/p>\n\n[1,2,<\/p>\n
‘c’,<\/p>\n
‘d’]<\/p>\n<\/div>\n
So, you can also pretty-print the output of the listdir() method or your system\u2019s environment variables with pprint(dict(os.environ),width=1).<\/span><\/p>\n>>> pprint(os.listdir())<\/pre>\nOutput<\/strong><\/p>\n\n[‘DLLs’,’Doc’,<\/p>\n
‘etc’,<\/p>\n
‘include’,<\/p>\n
‘Lib’,<\/p>\n
‘libs’,<\/p>\n
‘LICENSE.txt’,<\/p>\n
‘man’,<\/p>\n
‘NEWS.txt’,<\/p>\n
‘opencv_ffmpeg343.dll’,<\/p>\n
‘out.log’,<\/p>\n
‘python.exe’,<\/p>\n
‘python3.dll’,<\/p>\n
‘python37.dll’,<\/p>\n
‘pythonw.exe’,<\/p>\n
‘Scripts’,<\/p>\n
‘share’,<\/p>\n
‘tcl’,<\/p>\n
‘Tools’,<\/p>\n
‘vcruntime140.dll’]<\/p>\n<\/div>\n
You can use the <\/span>compact<\/span><\/i> flag to make this more compact-<\/span><\/p>\n>>> pprint(os.listdir(),compact=True)<\/pre>\nOutput<\/strong><\/p>\n\n[‘DLLs’, ‘Doc’, ‘etc’, ‘include’, ‘Lib’, ‘libs’, ‘LICENSE.txt’, ‘man’,’NEWS.txt’, ‘opencv_ffmpeg343.dll’, ‘out.log’, ‘python.exe’, ‘python3.dll’,<\/p>\n
‘python37.dll’, ‘pythonw.exe’, ‘Scripts’, ‘share’, ‘tcl’, ‘Tools’,<\/p>\n
‘vcruntime140.dll’]<\/p>\n<\/div>\n
The pprintpp Module<\/h3>\n
Before we say goodbye, why don\u2019t we talk about pprintpp? This is another module for pretty printing and we like to call it pprint++. <\/span><\/p>\nIt is available on PyPI, and you can install it as:<\/span><\/p>\nPython pip install pprintpp<\/pre>\nLet\u2019s import this.<\/span><\/p>\n>>> import pprintpp<\/pre>\nNow, let\u2019s try printing something with this.<\/span><\/p>\n>>> pprintpp.pprint(data)<\/pre>\n
This is just the kind of thing for aesthetics, and it keeps the output on a single line wherever possible. And when on multiple lines, it indents it.<\/span><\/p>\n Key features of pretty print in Python:<\/strong><\/p>\n Let\u2019s import it:<\/span><\/p>\n Basically, this module has the following classes:<\/span><\/p>\n class pprint.PrettyPrinter(indent=1, width=80, depth=None, stream=None, *, compact=False)<\/b><\/p>\n This constructs a PrettyPrinter instance for us. Let\u2019s talk about its parameters:<\/span><\/p>\n Now, let\u2019s try an example without pprint. Let\u2019s take a list to work with:<\/span><\/p>\n Output<\/strong><\/p>\n So, let\u2019s try printing this with pprint instead.<\/span><\/p>\n Output<\/strong><\/p>\n [(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}),(2,<\/p>\n {‘e’: ‘E’,<\/p>\n ‘f’: ‘F’,<\/p>\n ‘g’: ‘G’,<\/p>\n ‘h’: ‘H’,<\/p>\n ‘i’: ‘I’,<\/p>\n ‘j’: ‘J’,<\/p>\n ‘k’: ‘K’,<\/p>\n ‘l’: ‘L’}),<\/p>\n (3, [‘m’, ‘n’]),<\/p>\n (4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n (5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n So, what does Python pprint do? It formats an object and writes it to the data stream we pass to it as an argument. By default, this is sys.stdout.<\/span><\/p>\n We can format a data structure without having to write it to a stream. To do this, we use pformat() to build a string representation, and possible use cases include logging.<\/span><\/p>\n DEBUG \u00a0\u00a0\u00a0Logging pformatted data<\/strong><\/p>\n So, we can print or log this string independently:<\/span><\/p>\n Output<\/strong><\/p>\n DEBUG \u00a0\u00a0\u00a0[(1, {‘a’: ‘A’, ‘b’: ‘B’, ‘c’: ‘C’, ‘d’: ‘D’}),DEBUG \u00a0\u00a0\u00a0\u00a0(2,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0{‘e’: ‘E’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘f’: ‘F’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘g’: ‘G’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘h’: ‘H’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘i’: ‘I’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘j’: ‘J’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘k’: ‘K’,<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0‘l’: ‘L’}),<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0(3, [‘m’, ‘n’]),<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0(4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n DEBUG \u00a0\u00a0\u00a0\u00a0(5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n Last, we talked about the repr() built-in function in Python. In that, we observed the __repr__() method. <\/span><\/p>\n Today, let\u2019s see how we can make pprint work with our own classes by making use of the __repr__() method.<\/span><\/p>\n Output<\/strong><\/p>\n Now see what Python pprint does to this:<\/span><\/p>\n Output<\/strong><\/p>\n [I am salmon and you can find me at #FA8072,I am olive and you can find me at #808000,<\/p>\n I am purple and you can find me at #800080]<\/p>\n<\/div>\n Let\u2019s create a list and append it to its end. This makes for a recursive list.<\/span><\/p>\n Output<\/strong><\/p>\n Output<\/strong><\/p>\n #The recursive reference<\/span><\/p>\n Output<\/strong><\/p>\n To control how far the Python pretty printer recurses down a nested structure, we can use the <\/span>depth <\/span><\/i>argument:<\/span><\/p>\n Output<\/strong><\/p>\n Output<\/strong><\/p>\n Output<\/strong><\/p>\n ‘i’: ‘I’,<\/p>\n ‘j’: ‘J’,<\/p>\n ‘k’: ‘K’,<\/p>\n ‘l’: ‘L’}),<\/p>\n (3, [‘m’, ‘n’]),<\/p>\n (4, [‘o’, ‘p’, ‘q’, ‘r’, ‘s’, ‘t’, ‘u’, ‘v’, ‘w’]),<\/p>\n (5, [‘x’, ‘y’, ‘z’])]<\/p>\n<\/div>\n Here, the ellipses denote the levels it excludes from the output.<\/span><\/p>\n We can decide the width for the output- this is the number of columns. The default is 80, but we can change that with <\/span>width<\/span><\/i>.<\/span><\/p>\n Output<\/strong><\/p>\n Output<\/strong><\/p>\n [1,2,<\/p>\n ‘c’,<\/p>\n ‘d’]<\/p>\n<\/div>\n So, you can also pretty-print the output of the listdir() method or your system\u2019s environment variables with pprint(dict(os.environ),width=1).<\/span><\/p>\n Output<\/strong><\/p>\n [‘DLLs’,’Doc’,<\/p>\n ‘etc’,<\/p>\n ‘include’,<\/p>\n ‘Lib’,<\/p>\n ‘libs’,<\/p>\n ‘LICENSE.txt’,<\/p>\n ‘man’,<\/p>\n ‘NEWS.txt’,<\/p>\n ‘opencv_ffmpeg343.dll’,<\/p>\n ‘out.log’,<\/p>\n ‘python.exe’,<\/p>\n ‘python3.dll’,<\/p>\n ‘python37.dll’,<\/p>\n ‘pythonw.exe’,<\/p>\n ‘Scripts’,<\/p>\n ‘share’,<\/p>\n ‘tcl’,<\/p>\n ‘Tools’,<\/p>\n ‘vcruntime140.dll’]<\/p>\n<\/div>\n You can use the <\/span>compact<\/span><\/i> flag to make this more compact-<\/span><\/p>\n Output<\/strong><\/p>\n [‘DLLs’, ‘Doc’, ‘etc’, ‘include’, ‘Lib’, ‘libs’, ‘LICENSE.txt’, ‘man’,’NEWS.txt’, ‘opencv_ffmpeg343.dll’, ‘out.log’, ‘python.exe’, ‘python3.dll’,<\/p>\n ‘python37.dll’, ‘pythonw.exe’, ‘Scripts’, ‘share’, ‘tcl’, ‘Tools’,<\/p>\n ‘vcruntime140.dll’]<\/p>\n<\/div>\n Before we say goodbye, why don\u2019t we talk about pprintpp? This is another module for pretty printing and we like to call it pprint++. <\/span><\/p>\n It is available on PyPI, and you can install it as:<\/span><\/p>\n Let\u2019s import this.<\/span><\/p>\n Now, let\u2019s try printing something with this.<\/span><\/p>\n\n
>>> from pprint import pprint<\/pre>\n
\n
>>> data=[(1,{'a':'A','b':'B','c':'C','d':'D'}),(2,{'e':'E','f':'F','g':'G','h':'H','i':'I','j':'J','k':'K','l':'L'}),(3,['m','n']),(4,['o','p','q','r','s','t','u','v','w']),(5,['x','y','z']),]\r\n>>> print(data)<\/pre>\nPython pprint Example<\/h3>\n
>>> pprint(data)<\/pre>\n
Python pprint Formatting<\/h3>\n
>>> import logging\r\n>>> from pprint import pformat\r\n>>> logging.basicConfig(\r\n level=logging.DEBUG,\r\n format='%(levelname)-8s %(message)s',)\r\n>>> logging.debug('Logging pformatted data')<\/pre>\n>>> formatted=pformat(data)<\/pre>\n
>>> for line in formatted.splitlines():\r\n logging.debug(line.rstrip())<\/pre>\n
Pretty-Printing Our Own Classes in Python<\/h3>\n
>>> class Color:\r\n def __init__(self,name,hex_value):\r\n self.name=name\r\n self.hex_value=hex_value\r\n def __repr__(self):\r\n return(\r\n 'I am '+self.name+' and you can find me at '+self.hex_value)\r\n>>> colors=[Color('salmon','#FA8072'),Color('olive','#808000'),Color('purple','#800080')]\r\n>>> print(colors)<\/pre>\n>>> pprint(colors)<\/pre>\n
Python Pprint with Recursive Data Structures<\/h3>\n
>>> from pprint import pprint\r\n>>> mylist=[1,2,'c','d']\r\n>>> mylist.append(mylist)\r\n>>> id(mylist)<\/pre>\n
>>> pprint(mylist)<\/pre>\n
>>> mylist #Pay attention<\/pre>\n
\n
>>> pprint(data,depth=1)<\/pre>\n
>>> pprint(data,depth=2)<\/pre>\n
>>> pprint(data,depth=3)<\/pre>\n
\n\u00a0 \u00a0(2,<\/span>{‘e’: ‘E’,’f’: ‘F’,’g’: ‘G’,’h’: ‘H’,<\/p>\nDeciding Output Width<\/h3>\n
>>> mylist=[1,2,'c','d']\r\n>>> pprint(mylist)<\/pre>\n
>>> pprint(mylist,width=-1)<\/pre>\n
>>> pprint(os.listdir())<\/pre>\n
>>> pprint(os.listdir(),compact=True)<\/pre>\n
The pprintpp Module<\/h3>\n
Python pip install pprintpp<\/pre>\n
>>> import pprintpp<\/pre>\n
>>> pprintpp.pprint(data)<\/pre>\n