如何在Python中漂亮地打印深度为~4的字典?我尝试用pprint()进行漂亮的打印,但它不起作用:

import pprint 
pp = pprint.PrettyPrinter(indent=4)
pp.pprint(mydict)

我只是想要一个缩进(“\t”)为每个嵌套,这样我就会得到这样的东西:

key1
    value1
    value2
    key2
       value1
       value2

等。

我该怎么做呢?


当前回答

使用这个函数:

def pretty_dict(d, n=1):
    for k in d:
        print(" "*n + k)
        try:
            pretty_dict(d[k], n=n+4)
        except TypeError:
            continue

这样叫它:

pretty_dict(mydict)

其他回答

我不确定你到底想要什么样的格式,但你可以从这样一个函数开始:

def pretty(d, indent=0):
   for key, value in d.items():
      print('\t' * indent + str(key))
      if isinstance(value, dict):
         pretty(value, indent+1)
      else:
         print('\t' * (indent+1) + str(value))

我用了你们教我的东西加上装饰器的力量来重载经典的打印功能。只要根据需要改变缩进即可。我把它作为一个主旨在github,以防你想要星(保存)它。

def print_decorator(func):
    """
    Overload Print function to pretty print Dictionaries 
    """
    def wrapped_func(*args,**kwargs):
        if isinstance(*args, dict):
            return func(json.dumps(*args, sort_keys=True, indent=2, default=str))
        else:
            return func(*args,**kwargs)
    return wrapped_func
print = print_decorator(print)

现在就像往常一样使用打印。

晚了,但是这个答案不需要任何额外的库。类似于STH的答案,但在格式上更健壮一点,并返回一个完整的字符串,然后可以打印:

def pretty_print_dict(
        input_dictionary,
        indent=1,
        depth=0
):
    # Bool flag to add comma's after first item in dict.
    needs_comma = False
    # String for any dict will start with a '{'
    return_string = '\t' * depth + '{\n'
    # Iterate over keys and values, building the full string out.
    for key, value in input_dictionary.items():
        # Start with key. If key follows a previous item, add comma.
        if needs_comma:
            return_string = return_string + ',\n' + '\t' * (depth + 1) + str(key) + ': '
        else:
            return_string = return_string + '\t' * (depth + 1) + str(key) + ': '
        # If the value is a dict, recursively call function.
        if isinstance(value, dict):
            return_string = return_string + '\n' + pretty_print_dict(value, depth=depth+2)
        else:
            return_string = return_string + '\t' * indent + str(value)
        # After first line, flip bool to True to make sure commas make it.
        needs_comma = True
    # Complete the dict with a '}'
    return_string = return_string + '\n' + '\t' * depth + '}'
    # Return dict string.
    return return_string

让我们看看它如何处理像test_dict={1,2,3:{4:{5:6}, 7:8}, 9:10}这样的字典。

字符串的样子:“{\ n \ t1: \ t2, t3: \ n \ \ n \ t \ {\ n \ t \ \ t4: \ n \ t \ t \ \ {\ n \ t \ t \ \ \ t5: \ t6 \ n \ t \ t \ \ t}, \ n \ t \ \ t7: \ t8 \ n \ t \ t}, \ n \ t9: \ t10 \ n}”。

打印该字符串会得到:

{
    1:  2,
    3: 
        {
            4: 
                {
                    5:  6
                },
            7:  8
        },
    9:  10
}

至于已经做了什么,我没有看到任何漂亮的打印机,至少模仿python解释器的输出非常简单的格式,所以这里是我的:

class Formatter(object):
    def __init__(self):
        self.types = {}
        self.htchar = '\t'
        self.lfchar = '\n'
        self.indent = 0
        self.set_formater(object, self.__class__.format_object)
        self.set_formater(dict, self.__class__.format_dict)
        self.set_formater(list, self.__class__.format_list)
        self.set_formater(tuple, self.__class__.format_tuple)

    def set_formater(self, obj, callback):
        self.types[obj] = callback

    def __call__(self, value, **args):
        for key in args:
            setattr(self, key, args[key])
        formater = self.types[type(value) if type(value) in self.types else object]
        return formater(self, value, self.indent)

    def format_object(self, value, indent):
        return repr(value)

    def format_dict(self, value, indent):
        items = [
            self.lfchar + self.htchar * (indent + 1) + repr(key) + ': ' +
            (self.types[type(value[key]) if type(value[key]) in self.types else object])(self, value[key], indent + 1)
            for key in value
        ]
        return '{%s}' % (','.join(items) + self.lfchar + self.htchar * indent)

    def format_list(self, value, indent):
        items = [
            self.lfchar + self.htchar * (indent + 1) + (self.types[type(item) if type(item) in self.types else object])(self, item, indent + 1)
            for item in value
        ]
        return '[%s]' % (','.join(items) + self.lfchar + self.htchar * indent)

    def format_tuple(self, value, indent):
        items = [
            self.lfchar + self.htchar * (indent + 1) + (self.types[type(item) if type(item) in self.types else object])(self, item, indent + 1)
            for item in value
        ]
        return '(%s)' % (','.join(items) + self.lfchar + self.htchar * indent)

要初始化它:

pretty = Formatter()

它可以支持为已定义的类型添加格式化器,你只需要为它创建一个函数,然后用set_formater将它绑定到你想要的类型:

from collections import OrderedDict

def format_ordereddict(self, value, indent):
    items = [
        self.lfchar + self.htchar * (indent + 1) +
        "(" + repr(key) + ', ' + (self.types[
            type(value[key]) if type(value[key]) in self.types else object
        ])(self, value[key], indent + 1) + ")"
        for key in value
    ]
    return 'OrderedDict([%s])' % (','.join(items) +
           self.lfchar + self.htchar * indent)
pretty.set_formater(OrderedDict, format_ordereddict)

由于历史原因,我保留了之前的漂亮打印机,它是一个函数而不是一个类,但它们都可以以同样的方式使用,类版本只是允许更多:

def pretty(value, htchar='\t', lfchar='\n', indent=0):
    nlch = lfchar + htchar * (indent + 1)
    if type(value) is dict:
        items = [
            nlch + repr(key) + ': ' + pretty(value[key], htchar, lfchar, indent + 1)
            for key in value
        ]
        return '{%s}' % (','.join(items) + lfchar + htchar * indent)
    elif type(value) is list:
        items = [
            nlch + pretty(item, htchar, lfchar, indent + 1)
            for item in value
        ]
        return '[%s]' % (','.join(items) + lfchar + htchar * indent)
    elif type(value) is tuple:
        items = [
            nlch + pretty(item, htchar, lfchar, indent + 1)
            for item in value
        ]
        return '(%s)' % (','.join(items) + lfchar + htchar * indent)
    else:
        return repr(value)

使用它:

>>> a = {'list':['a','b',1,2],'dict':{'a':1,2:'b'},'tuple':('a','b',1,2),'function':pretty,'unicode':u'\xa7',("tuple","key"):"valid"}
>>> a
{'function': <function pretty at 0x7fdf555809b0>, 'tuple': ('a', 'b', 1, 2), 'list': ['a', 'b', 1, 2], 'dict': {'a': 1, 2: 'b'}, 'unicode': u'\xa7', ('tuple', 'key'): 'valid'}
>>> print(pretty(a))
{
    'function': <function pretty at 0x7fdf555809b0>,
    'tuple': (
        'a',
        'b',
        1,
        2
    ),
    'list': [
        'a',
        'b',
        1,
        2
    ],
    'dict': {
        'a': 1,
        2: 'b'
    },
    'unicode': u'\xa7',
    ('tuple', 'key'): 'valid'
}

相对于其他版本:

This solution looks directly for object type, so you can pretty print almost everything, not only list or dict. Doesn't have any dependancy. Everything is put inside a string, so you can do whatever you want with it. The class and the function has been tested and works with Python 2.7 and 3.4. You can have all type of objects inside, this is their representations and not theirs contents that being put in the result (so string have quotes, Unicode string are fully represented ...). With the class version, you can add formatting for every object type you want or change them for already defined ones. key can be of any valid type. Indent and Newline character can be changed for everything we'd like. Dict, List and Tuples are pretty printed.

最简单的方法是安装IPython并使用如下所示的方法

from IPython.lib.pretty import pretty


class MyClass:
    __repr__(self):
       return pretty(data)  # replace data with what makes sense

在你的情况下

print(pretty(mydict))