pprint 是 “pretty printer” 的简写，“pretty” 的含义是 “漂亮的、美观的”，因此 pprint 的含义便是：漂亮的打印。

这是个相当简单却有用的模块，主要用于打印复杂的数据结构对象，例如多层嵌套的列表、元组和字典等。

先看看 print() 打印的一个例子：

mylist = ["Beautiful is better than ugly.", "Explicit is better than implicit.", "Simple is better than complex.", "Complex is better than complicated."]

print(mylist)

['Beautiful is better than ugly.', 'Explicit is better than implicit.', 'Simple is better than complex.', 'Complex is better than complicated.']
这是一个简单的例子，全部打印在一行里。如果对象中的元素是多层嵌套的内容（例如复杂的 字典 数据），再打印出那肯定是一团糟的，不好阅读。

使用 pprint 模块的 pprint() 替代 print()，可以解决如下痛点：

设置合适的行宽度，作适当的换行
设置打印的缩进、层级，进行格式化打印
判断对象中是否有无限循环，并优化打印内容
基本使用

pprint(object, stream=None, indent=1, width=80, depth=None, *,compact=False)
默认的行宽度参数为 80，当打印的字符小于 80 时，pprint() 基本上等同于内置函数 print()，当字符超出时，它会作美化，进行格式化输出。

import pprint

mylist = ["Beautiful is better than ugly.", "Explicit is better than implicit.", "Simple is better than complex.", "Complex is better than complicated."]

pprint.pprint(mylist)

超出80字符，打印的元素是换行的

['Beautiful is better than ugly.',
'Explicit is better than implicit.',
'Simple is better than complex.',
'Complex is better than complicated.']
设置缩进

pprint.pprint(mylist, indent=4)

[ 'Beautiful is better than ugly.',

'Explicit is better than implicit.',
'Simple is better than complex.',
'Complex is better than complicated.']

设置打印行宽

mydict = {'students': [{'name':'Tom', 'age': 18},{'name':'Jerry', 'age': 19}]}

pprint.pprint(mydict)

正常打印

{'students': [{'age': 18, 'name': 'Tom'}, {'age': 19, 'name': 'Jerry'}]}

pprint.pprint(mydict, width=20)

行宽为 20

{'students': [{'age': 18,

           'name': 'Tom'},
          {'age': 19,
           'name': 'Jerry'}]}

pprint.pprint(mydict, width=70)

行宽为 70

{'students': [{'age': 18, 'name': 'Tom'},

          {'age': 19, 'name': 'Jerry'}]}

设置打印层级

newlist = [1, [2, [3, [4, [5]]]]]

pprint.pprint(newlist, depth=3)

超出的层级会用 ... 表示

[1, [2, [3, [...]]]]
用 pprint 替换 print

import pprint
print = pprint.pprint

mylist = ["Beautiful is better than ugly.", "Explicit is better than implicit.", "Simple is better than complex.", "Complex is better than complicated."]

print(mylist)

['Beautiful is better than ugly.',
'Explicit is better than implicit.',
'Simple is better than complex.',
'Complex is better than complicated.']
更多用法请查看官方文档
总体而言，pprint() 是 print() 的轻量级替代，简单实用，非常方便，而且还是 Python 标准库。