C ++标准是否保证以下代码正确?
import plotly.graph_objects as go
import numpy as np
np.random.seed(42)
y0 = np.random.randn(50)
y1 = np.random.randn(50) + 1
y2 = np.random.randn(50) + 2 # shift mean
x0 = 'Sample A'
x1 = 'Sample B'
x2 = 'Sample C'
fig = go.Figure()
fig.add_trace(go.Scatter(
y=[x0]*len(y0),
x=y0,
mode='markers',
name='Sample A',
legendgroup='A',
showlegend=False
))
fig.add_trace(go.Scatter(
y=[x1]*len(y1),
x=y1,
mode='markers',
name='Sample B',
legendgroup='B',
showlegend=False
))
fig.add_trace(go.Scatter(
y=[x2]*len(y2),
x=y2,
mode='markers',
name='Sample C',
legendgroup='C',
showlegend=False
))
fig.add_trace(go.Box(
x=y0,
name='Sample A',
marker_color = 'indianred',
boxpoints=False,
legendgroup='A',
yaxis='y2'
))
fig.add_trace(go.Box(
x=y1,
name='Sample B',
marker_color = 'lightseagreen',
boxpoints=False,
legendgroup='B',
yaxis='y2'
))
fig.add_trace(go.Box(
x=y2,
name='Sample C',
marker_color = 'orange',
boxpoints=False,
legendgroup='C',
yaxis='y2'
))
fig.update_layout(
yaxis2=dict(
matches='y',
layer="above traces",
overlaying="y",
showticklabels=False
))
fig.show()
(至少它与同时具有#include <iostream>
#include <vector>
std::vector<int>::iterator i = {};
int main()
{
if (i == std::vector<int>::iterator{})
{
std::cout << "it is empty" << std::endl;
}
return 0;
}
和std::vector<int>
的MSVC2017一起使用)