Python 将嵌套JSON中的值添加到数据帧

我有以下JSON对象：

{"code":"Ok","matchings":[{"confidence":0.025755,"geometry":"qnp{bBww{kH??~D_I}E_J{EaJ{E{I{AsCoJgQfKuTjJwNtF}HdBuBnAgBpFsF~EeEzAsAt@i@lA}@x@q@lEmCjDuBdDoAvFmAfYmEtAUrJyDj@_@h@m@`@u@T}@J{@B_A?gAGmAM}@Su@]u@wN{QwI{KcA}Aa@gASiAWsBOwCGmDCoJ??cEH?{FA{HgIXuG`@eHrAsLdDkI|CkIfDq@VoDlB_GzDaE`D_A|@kA`AeAx@sI~G}DlDk@j@mClCiOrQwGvJiGxJoFdK_HjP{Pne@aLt\\sK~]oKb_@sG~TeJ`_@q@fD{@dEoBlMwBxQaAbI{Dh\\wKrfAiRbvBy@`KaLjwAyHj_AANM~AUxC}@tKi@bHe@jGfBj@t@V|@\\TFjAXz@HhASxAy@vCcBjX~GvG`BlEjAv\\xJfBf@dThG~Ad@nFrBnCbBdCvBzB`DbCfEr{@b~A","legs":[{"annotation":{"nodes":[330029575,5896466632,330029575,5896466588,5896466587,5896466586,5896466637,330029340,330029339,330029338,1497356855,1880770263,46388213,1880770262,1880770257,2021835257,3306177380,46387099,2021835255,6909770873,46385948,6909770874,46384887,46382454]},"steps":[],"distance":332.2,"duration":93.1,"summary":"","weight":93.1},{"annotation":{"nodes":[46384887,46382454,5888264001,6909802199,3296872014,6909802198,5888264003,6909802197,3296872012,6909802194,6909802195,6909802193,6909802196,3296872013,3296872015]},"steps":[],"distance":88.1,"duration":13.5,"summary":"","weight":13.5},{"annotation":{"nodes":[3296872013,3296872015,6909802186,6909802187,6909770884,3296872017,6909802185,4904066416,3296872018,1614187163]},"steps":[],"distance":62.3,"duration":12.4,"summary":"","weight":12.4},{"annotation":{"nodes":[3296872018,1614187163,2054127599,1614187129,5896479942,6909802219,46384372,1027299576,6909802220,46389815]},"steps":[],"distance":144,"duration":25.2,"summary":"","weight":25.2},{"annotation":{"nodes":[6909802220,46389815,6296436095,6296436094,298079716,6296436096,46391324,1083528076,6909802221,6909802222,46393158]},"steps":[],"distance":90.6,"duration":10.1,"summary":"","weight":10.1},{"annotation":{"nodes":[6909802222,46393158,46393795,6909802223,1027299602,6909802224,46396846,46398397,2054127645,46399502,46400708,1027299589,6712474212,6903665704,46402805,46403163,4374153462]},"steps":[],"distance":422.9,"duration":40.1,"summary":"","weight":40.1},{"annotation":{"nodes":[46403163,4374153462,46404084,1027299603,364146312,2262500170]},"steps":[],"distance":273.6,"duration":24.7,"summary":"","weight":24.7},{"annotation":{"nodes":[364146312,2262500170,5289718695]},"steps":[],"distance":170.9,"duration":15.3,"summary":"","weight":15.3},{"annotation":{"nodes":[2262500170,5289718695,2054127657,1693195716,46408565,6913837768,1693195721,2262500247,1693195714,2262500104,1693195717]},"steps":[],"distance":56.9,"duration":14.2,"summary":"","weight":14.2},{"annotation":{"nodes":[46397705,46401323,46405521]},"steps":[],"distance":86.6,"duration":12.6,"summary":"","weight":12.6},{"annotation":{"nodes":[46401323,46405521,46410773]},"steps":[],"distance":156.5,"duration":22.5,"summary":"","weight":22.5},{"annotation":{"nodes":[46405521,46410773,452003319,452003320]},"steps":[],"distance":95.4,"duration":13.8,"summary":"","weight":13.8},{"annotation":{"nodes":[452003319,452003320,46411428,46414457,46419384,46421801]},"steps":[],"distance":226.4,"duration":32.6,"summary":"","weight":32.6},{"annotation":{"nodes":[46419384,46421801,46421802,46421735]},"steps":[],"distance":69.2,"duration":10,"summary":"","weight":10},{"annotation":{"nodes":[46421802,46421735,46421416]},"steps":[],"distance":34.1,"duration":4.9,"summary":"","weight":4.9},{"annotation":{"nodes":[46421735,46421416,46420466]},"steps":[],"distance":2.7,"duration":0.3,"summary":"","weight":0.3},{"annotation":{"nodes":[46421416,46420466]},"steps":[],"distance":31.4,"duration":4.6,"summary":"","weight":4.6},{"annotation":{"nodes":[46421416,46420466,452003307,452003308,46421260,46422467,5761752102,46423905]},"steps":[],"distance":135.5,"duration":25,"summary":"","weight":25},{"annotation":{"nodes":[5761752102,46423905,46424346,5777055555,5713213408,46425605,5777055050,5777346784,5777055556,5713221227,46426685,46427741,3175895442,3183752428,5826014405,46428227]},"steps":[],"distance":106.5,"duration":14.9,"summary":"","weight":14.9},{"annotation":{"nodes":[5826014405,46428227,3175895443,5826014406,3175895444,5826014368,5826014369,5826014374,46429570,5826014373,5826014375,5826014372,5826014358,5826014371,5826014370,5826014376]},"steps":[],"distance":172.7,"duration":15.7,"summary":"","weight":15.7},{"annotation":{"nodes":[2054127660,2054127638,2054127605,6296435009,2054127599,6909770882,3296872018,4904066416,6909802185,3296872017,6909770884,6909802187,6909802186,3296872015,3296872013,6909802196,6909802193,6909802195,6909802194,3296872012,6909802197,5888264003,6909802198,3296872014,6909802199,5888264001,46382454,46384887,6909770874,46385948,6909770873,2021835255,46387099,3306177380,2021835257]},"steps":[],"distance":317.7,"duration":46.1,"summary":"","weight":46.1},{"annotation":{"nodes":[3306177380,2021835257,1880770257,1880770262,46388213,1880770263,1497356855,330029338,330029339,330029340,5896466637]},"steps":[],"distance":150.4,"duration":29.4,"summary":"","weight":29.4}],"distance":80317.8,"duration":10983.5,"weight_name":"duration","weight":10983.5}],"tracepoints":[{"alternatives_count":0,"waypoint_index":0,"matchings_index":0,"location":[4.929932,52.372217],"name":"Willem Theunisse Blokstraat","distance":10.791613,"hint":"CAkHgHAJBwAlAAAAAAAAAAAAAAAAAAAALCd0QQAAAAAAAAAAAAAAACUAAAAAAAAAAAAAAAAAAAABAAAAjDlLAPkiHwP3OEsAGiMfAwAArxMz7Ejh"},null,{"alternatives_count":0,"waypoint_index":1,"matchings_index":0,"location":[4.932506,52.3709],"name":"Frans de Wollantstraat","distance":11.915926,"hint":"pwUBAPYEAYAHAAAARwAAAAAAAAAAAAAA3_qaQE0JPUIAAAAAAAAAAAcAAABHAAAAAAAAAAAAAAABAAAAmkNLANQdHwPtQksAxB0fAwAA_xUz7Ejh"},{"alternatives_count":0,"waypoint_index":472,"matchings_index":0,"location":[4.932745,52.373288],"name":"Piet Heinkade","distance":0.98867,"hint":"gwUBgMgFAQAFAAAADQAAABoBAABYAAAAQMS3QHTNW0HsWZ1DmZ2WQgUAAAANAAAAGgEAAFgAAAABAAAAiURLACgnHwN9REsAIycfAwoADwkz7Ejh"},null,null,{"alternatives_count":1,"waypoint_index":473,"matchings_index":0,"location":[4.934022,52.371637],"name":"Piet Heinkade","distance":2.713742,"hint":"NA8HADsPB4ACAAAADwAAADoAAAA-AAAAjU82QIAqg0FUpSdCLoWJQgIAAAAPAAAAOgAAAD4AAAABAAAAhklLALUgHwNfSUsAsCAfAwQAvxUz7Ejh"},null,null,{"alternatives_count":1,"waypoint_index":474,"matchings_index":0,"location":[4.93213,52.371794],"name":"Frans de Wollantstraat","distance":10.337677,"hint":"AgUBgAcFAQABAAAABAAAAAwAAAAAAAAA1paeP-KrBUAomAdBAAAAAAEAAAAEAAAADAAAAAAAAAABAAAAIkJLAFIhHwOrQksAeiEfAwIA7xQz7Ejh"},{"alternatives_count":1,"waypoint_index":475,"matchings_index":0,"location":[4.93074,52.372528],"name":"Isaac Titsinghkade","distance":0.65222,"hint":"AwkHgAYJBwA5AAAACwAAAAAAAACMAAAA_Fe_QWP_k0AAAAAA33FqQjkAAAALAAAAAAAAAIwAAAABAAAAtDxLADAkHwOtPEsANCQfAwAADw4z7Ejh"},null,null]}

我想将属于键

节点的所有值添加到数据帧中的一列中

当我跑步时：

for i in output["matchings"][0]['legs']:
    result  = i['annotation']['nodes']
df = pd.DataFrame(result, columns=['node'])
df

只有一小部分被添加到数据帧中。我做错了什么？
在for循环的末尾，“df”保留json的最后一个“node”键。您必须将所有“节点”键附加到单个数据帧中

扩展代码：

df = pd.DataFrame({'node':{}})

for i in output["matchings"][0]['legs']:
    result  = i['annotation']['nodes']
    df_temp = pd.DataFrame(result, columns=['node'])
    df = df.append(df_temp, ignore_index=True)