Question

我使用以下代码在Python中打印json：

json.dumps(json_output, indent=2, separators=(',', ': ')

这会打印我的json，如：

{    
    "rows_parsed": [
        [
          "a",
          "b",
          "c",
          "d"
        ],
        [
          "e",
          "f",
          "g",
          "i"
        ],
    ]
}

但是，我希望它打印如下：

{    
    "rows_parsed": [
        ["a","b","c","d"],
        ["e","f","g","i"],
    ]
}

如何将数组中的数组全部保存在一行上？

Answer 1

这是一种进行最少修改的方法：

import json
from json import JSONEncoder
import re

class MarkedList:
    _list = None
    def __init__(self, l):
        self._list = l

z = {    
    "rows_parsed": [
        MarkedList([
          "a",
          "b",
          "c",
          "d"
        ]),
        MarkedList([
          "e",
          "f",
          "g",
          "i"
        ]),
    ]
}

class CustomJSONEncoder(JSONEncoder):
    def default(self, o):
        if isinstance(o, MarkedList):
            return "##<{}>##".format(o._list)

b = json.dumps(z, indent=2, separators=(',', ':'), cls=CustomJSONEncoder)
b = b.replace('"##<', "").replace('>##"', "")

print(b)

基本上，您要作为实例的格式要格式化的列表 MarkedList，然后将它们解析为具有唯一唯一顺序的字符串稍后从dumps的输出中删除。这样做是为了消除放在json字符串周围的引号。

另一种更有效的方法，但更丑陋的方法是修补猴子 json.encoder._make_iterencode._iterencode，内容类似：

def _iterencode(o, _current_indent_level):
    if isinstance(o, str):
        yield _encoder(o)
    elif o is None:
        yield 'null'
    elif o is True:
        yield 'true'
    elif o is False:
        yield 'false'
    elif isinstance(o, int):
        # see comment for int/float in _make_iterencode
        yield _intstr(o)
    elif isinstance(o, float):
        # see comment for int/float in _make_iterencode
        yield _floatstr(o)
    elif isinstance(o, MarkedList):
        yield _my_custom_parsing(o)
    elif isinstance(o, (list, tuple)):
        yield from _iterencode_list(o, _current_indent_level)
    elif isinstance(o, dict):
        yield from _iterencode_dict(o, _current_indent_level)
    else:
        if markers is not None:
            markerid = id(o)
            if markerid in markers:
                raise ValueError("Circular reference detected")
            markers[markerid] = o
        o = _default(o)
        yield from _iterencode(o, _current_indent_level)
        if markers is not None:
            del markers[markerid]

Answer 2

我看不到如何在json.dumps中做到这一点。经过一番搜索，我遇到了一些选择：一种选择是使用自定义函数进行一些后处理：

def fix_json_indent(text, indent=3):
            space_indent = indent * 4
    initial = " " * space_indent
    json_output = []
    current_level_elems = []
    all_entries_at_level = None  # holder for consecutive entries at exact space_indent level
    for line in text.splitlines():
        if line.startswith(initial):
            if line[space_indent] == " ":
                # line indented further than the level
                if all_entries_at_level:
                    current_level_elems.append(all_entries_at_level)
                    all_entries_at_level = None
                item = line.strip()
                current_level_elems.append(item)
                if item.endswith(","):
                    current_level_elems.append(" ")
            elif current_level_elems:
                # line on the same space_indent level
                # no more sublevel_entries 
                current_level_elems.append(line.strip())
                json_output.append("".join(current_level_elems))
                current_level_elems = []
            else:
                # line at the exact space_indent level but no items indented further
                if all_entries_at_level:
                    # last pending item was not the start of a new sublevel_entries.
                    json_output.append(all_entries_at_level)
                all_entries_at_level = line.rstrip()
        else:
            if all_entries_at_level:
                json_output.append(all_entries_at_level)
                all_entries_at_level = None
            if current_level_elems:
                json_output.append("".join(current_level_elems))
            json_output.append(line)
    return "\n".join(json_output)

另一种可能是正则表达式，但是它很难看，取决于您发布的代码的结构：

def fix_json_indent(text):
    import re
    return  re.sub('{"', '{\n"', re.sub('\[\[', '[\n[', re.sub('\]\]', ']\n]', re.sub('}', '\n}', text))))

相当打印json但保持内部数组在一行python

2 个答案: