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

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。

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))

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)

从这个链接:

def prnDict(aDict, br='\n', html=0,
            keyAlign='l',   sortKey=0,
            keyPrefix='',   keySuffix='',
            valuePrefix='', valueSuffix='',
            leftMargin=0,   indent=1 ):
    '''
return a string representive of aDict in the following format:
    {
     key1: value1,
     key2: value2,
     ...
     }

Spaces will be added to the keys to make them have same width.

sortKey: set to 1 if want keys sorted;
keyAlign: either 'l' or 'r', for left, right align, respectively.
keyPrefix, keySuffix, valuePrefix, valueSuffix: The prefix and
   suffix to wrap the keys or values. Good for formatting them
   for html document(for example, keyPrefix='<b>', keySuffix='</b>'). 
   Note: The keys will be padded with spaces to have them
         equally-wide. The pre- and suffix will be added OUTSIDE
         the entire width.
html: if set to 1, all spaces will be replaced with '&nbsp;', and
      the entire output will be wrapped with '<code>' and '</code>'.
br: determine the carriage return. If html, it is suggested to set
    br to '<br>'. If you want the html source code eazy to read,
    set br to '<br>\n'

version: 04b52
author : Runsun Pan
require: odict() # an ordered dict, if you want the keys sorted.
         Dave Benjamin 
         http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/161403
    '''

    if aDict:

        #------------------------------ sort key
        if sortKey:
            dic = aDict.copy()
            keys = dic.keys()
            keys.sort()
            aDict = odict()
            for k in keys:
                aDict[k] = dic[k]

        #------------------- wrap keys with ' ' (quotes) if str
        tmp = ['{']
        ks = [type(x)==str and "'%s'"%x or x for x in aDict.keys()]

        #------------------- wrap values with ' ' (quotes) if str
        vs = [type(x)==str and "'%s'"%x or x for x in aDict.values()] 

        maxKeyLen = max([len(str(x)) for x in ks])

        for i in range(len(ks)):

            #-------------------------- Adjust key width
            k = {1            : str(ks[i]).ljust(maxKeyLen),
                 keyAlign=='r': str(ks[i]).rjust(maxKeyLen) }[1]

            v = vs[i]        
            tmp.append(' '* indent+ '%s%s%s:%s%s%s,' %(
                        keyPrefix, k, keySuffix,
                        valuePrefix,v,valueSuffix))

        tmp[-1] = tmp[-1][:-1] # remove the ',' in the last item
        tmp.append('}')

        if leftMargin:
          tmp = [ ' '*leftMargin + x for x in tmp ]

        if html:
            return '<code>%s</code>' %br.join(tmp).replace(' ','&nbsp;')
        else:
            return br.join(tmp)     
    else:
        return '{}'

'''
Example:

>>> a={'C': 2, 'B': 1, 'E': 4, (3, 5): 0}

>>> print prnDict(a)
{
 'C'   :2,
 'B'   :1,
 'E'   :4,
 (3, 5):0
}

>>> print prnDict(a, sortKey=1)
{
 'B'   :1,
 'C'   :2,
 'E'   :4,
 (3, 5):0
}

>>> print prnDict(a, keyPrefix="<b>", keySuffix="</b>")
{
 <b>'C'   </b>:2,
 <b>'B'   </b>:1,
 <b>'E'   </b>:4,
 <b>(3, 5)</b>:0
}

>>> print prnDict(a, html=1)
<code>{
&nbsp;'C'&nbsp;&nbsp;&nbsp;:2,
&nbsp;'B'&nbsp;&nbsp;&nbsp;:1,
&nbsp;'E'&nbsp;&nbsp;&nbsp;:4,
&nbsp;(3,&nbsp;5):0
}</code>

>>> b={'car': [6, 6, 12], 'about': [15, 9, 6], 'bookKeeper': [9, 9, 15]}

>>> print prnDict(b, sortKey=1)
{
 'about'     :[15, 9, 6],
 'bookKeeper':[9, 9, 15],
 'car'       :[6, 6, 12]
}

>>> print prnDict(b, keyAlign="r")
{
        'car':[6, 6, 12],
      'about':[15, 9, 6],
 'bookKeeper':[9, 9, 15]
}
'''

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.

我只是在得到某事物的答案并做了一个很小但非常有用的修改之后回到这个问题。该函数打印JSON树中的所有键以及该树中叶节点的大小。

def print_JSON_tree(d, indent=0):
    for key, value in d.iteritems():
        print '    ' * indent + unicode(key),
        if isinstance(value, dict):
            print; print_JSON_tree(value, indent+1)
        else:
            print ":", str(type(d[key])).split("'")[1], "-", str(len(unicode(d[key])))

当您有大型JSON对象并想要找出肉在哪里时,这非常好。例子:

>>> print_JSON_tree(JSON_object)
key1
    value1 : int - 5
    value2 : str - 16
    key2
       value1 : str - 34
       value2 : list - 5623456

这将告诉您,您所关心的大部分数据可能在JSON_object['key1']['key2']['value2']中,因为该值格式化为字符串的长度非常大。