这个问题在我做173时就发生了。关于leetcode的二进制搜索树迭代器：
ValueError Traceback (most recent call last)
<ipython-input-63-2c9a8a530884> in <module>()
3 'values': temp.values
4 })
----> 5 df.iplot(kind='scatter',labels='labels',values='values', title='Loan
Repayed or not')
C:\ProgramData\Anaconda3\lib\site-packages\cufflinks\plotlytools.py in
_iplot(self, data, layout, filename, sharing, kind, title, xTitle, yTitle,
zTitle, theme, colors, colorscale, fill, width, dash, mode, symbol, size,
barmode, sortbars, bargap, bargroupgap, bins, histnorm, histfunc,
orientation,
boxpoints, annotations, keys, bestfit, bestfit_colors, mean, mean_colors,
categories, x, y, z, text, gridcolor, zerolinecolor, margin, labels, values,
secondary_y, secondary_y_title, subplots, shape, error_x, error_y,
error_type,
locations, lon, lat, asFrame, asDates, asFigure, asImage, dimensions, asPlot,
asUrl, online, **kwargs)
698
bargap=bargap,bargroupgap=bargroupgap,
annotations=annotations,gridcolor=gridcolor
,
699
dimensions=dimensions,
--> 700
zerolinecolor=zerolinecolor,margin=margin,is3d='3d' in kind,**l_kwargs)
701
702 if not data:
C:\ProgramData\Anaconda3\lib\site-packages\cufflinks\tools.py in
getLayout(kind,
theme, title, xTitle, yTitle, zTitle, barmode, bargap, bargroupgap, margin,
dimensions, width, height, annotations, is3d, **kwargs)
197
198 theme_data = getTheme(theme)
--> 199 layout=Layout(theme_data['layout'])
200 layout['xaxis1'].update({'title':xTitle})
201 layout['yaxis1'].update({'title':yTitle})
C:\ProgramData\Anaconda3\lib\site-packages\plotly\graph_objs\_layout.py in
__init__(self, arg, angularaxis, annotations, autosize, bargap, bargroupgap,
barmode, barnorm, boxgap, boxgroupgap, boxmode, calendar, colorway,
datarevision,
direction, dragmode, font, geo, grid, height, hiddenlabels, hiddenlabelssrc,
hidesources, hoverdistance, hoverlabel, hovermode, images, legend, mapbox,
margin, orientation, paper_bgcolor, plot_bgcolor, polar, radialaxis, scene,
selectdirection, separators, shapes, showlegend, sliders, spikedistance,
template, ternary, title, titlefont, updatemenus, violingap, violingroupgap,
violinmode, width, xaxis, yaxis, **kwargs)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setattr__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setattr__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\graph_objs\_layout.py in
legend(self, val)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setitem__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setitem__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
_set_compound_prop(self, prop, val)
C:\ProgramData\Anaconda3\lib\site-packages\_plotly_utils\basevalidators.py in
validate_coerce(self, v)
C:\ProgramData\Anaconda3\lib\site-
packages\plotly\graph_objs\layout\_legend.py in
__init__(self, arg, bgcolor, bordercolor, borderwidth, font, orientation,
tracegroupgap, traceorder, x, xanchor, y, yanchor, **kwargs)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setattr__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-
packages\plotly\graph_objs\layout\_legend.py in
bgcolor(self, val)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
__setitem__(self, prop, value)
C:\ProgramData\Anaconda3\lib\site-packages\plotly\basedatatypes.py in
_set_prop(self, prop, val)
C:\ProgramData\Anaconda3\lib\site-packages\_plotly_utils\basevalidators.py in
validate_coerce(self, v, should_raise)
C:\ProgramData\Anaconda3\lib\site-packages\_plotly_utils\basevalidators.py in
raise_invalid_val(self, v)
ValueError:
Invalid value of type 'builtins.str' received for the 'bgcolor' property of
layout.legend
Received value: 'pearl02'
The 'bgcolor' property is a color and may be specified as:
- A hex string (e.g. '#ff0000')
- An rgb/rgba string (e.g. 'rgb(255,0,0)')
- An hsl/hsla string (e.g. 'hsl(0,100%,50%)')
- An hsv/hsva string (e.g. 'hsv(0,100%,100%)')
- A named CSS color:
aliceblue, antiquewhite, aqua, aquamarine, azure,
beige, bisque, black, blanchedalmond, blue,
blueviolet, brown, burlywood, cadetblue,
chartreuse, chocolate, coral, cornflowerblue,
cornsilk, crimson, cyan, darkblue, darkcyan,
darkgoldenrod, darkgray, darkgrey, darkgreen,
darkkhaki, darkmagenta, darkolivegreen, darkorange,
darkorchid, darkred, darksalmon, darkseagreen,
darkslateblue, darkslategray, darkslategrey,
darkturquoise, darkviolet, deeppink, deepskyblue,
dimgray, dimgrey, dodgerblue, firebrick,
floralwhite, forestgreen, fuchsia, gainsboro,
ghostwhite, gold, goldenrod, gray, grey, green,
greenyellow, honeydew, hotpink, indianred, indigo,
ivory, khaki, lavender, lavenderblush, lawngreen,
lemonchiffon, lightblue, lightcoral, lightcyan,
lightgoldenrodyellow, lightgray, lightgrey,
lightgreen, lightpink, lightsalmon, lightseagreen,
lightskyblue, lightslategray, lightslategrey,
lightsteelblue, lightyellow, lime, limegreen,
linen, magenta, maroon, mediumaquamarine,
mediumblue, mediumorchid, mediumpurple,
mediumseagreen, mediumslateblue, mediumspringgreen,
mediumturquoise, mediumvioletred, midnightblue,
mintcream, mistyrose, moccasin, navajowhite, navy,
oldlace, olive, olivedrab, orange, orangered,
orchid, palegoldenrod, palegreen, paleturquoise,
palevioletred, papayawhip, peachpuff, peru, pink,
plum, powderblue, purple, red, rosybrown,
royalblue, saddlebrown, salmon, sandybrown,
seagreen, seashell, sienna, silver, skyblue,
slateblue, slategray, slategrey, snow, springgreen,
steelblue, tan, teal, thistle, tomato, turquoise,
violet, wheat, white, whitesmoke, yellow,
yellowgreen
然后当我运行时：
class TreeNode(object):
def __init__(self, x):
self.val = x
self.left = None
self.right = None
class BSTIterator(object):
def __init__(self, root):
"""
:type root: TreeNode
"""
self.root = root
def next(self):
"""
:rtype: int
"""
self.point = self.root
while self.point.left:
self.point = self.point.left
#self.point = self.point.left
#self.point.val = 1000
self.point = None
我期望None，但是无论如何它返回1。有什么解释吗？
答案 0 :(得分：0)
之所以无法获得None是因为您根本没有更改self.root。而是在下一个函数中创建self.point，仅对self.point进行突变。
您可以在底部添加一行。
print(iterat.point)
它将返回您，
None