Matplotlib 显示额外的 x 标签集与常规 x 标签重叠

Question

我在使用 matplotlib 时遇到了这个问题，我无法隐藏自动生成的、不需要的 xlabels，这些 xlabels 似乎是凭空冒出来的。

这是我的代码（在这个重现问题的最小示例中减少了实际代码）：

import datetime as dt
import matplotlib.pyplot as plt
import pandas as pd

data = pd.read_csv("TestData.csv")

# Convert string to pd.Timestamp
data["datetime"] = data["datetime"].transform(lambda d:
                              dt.datetime.strptime(d, '%Y-%m-%d %H:%M:%S'))
data.set_index("datetime")

# start and end dates of data in CSV
max_date = data["datetime"].max()
min_date = data["datetime"].min()

# make figure
fig = plt.figure(figsize=[24, 12], dpi=300)

ax = data.plot.line(x="datetime",
                    y="totalAIAD",
                    color="xkcd:aquamarine")

delta = max_date - min_date  # total span of time for the report

time_unit = pd.to_timedelta(5, unit='m')  # 5 minute ticks
floor_unit = 'T'

# floor for cleaner ticks
date = min_date.floor(floor_unit)
xticks = []

while date + time_unit <= max_date:
    date = date + time_unit  # create date ticks for x axis

    xticks.append(date)

ax.axes.set_xticks(xticks)

str_xticks = []
for xtick in xticks:
    str_xticks.append(xtick.strftime('%H:%M:%S'))

ax.axes.set_xticklabels(str_xticks, rotation=45, ha='right')

#plt.suptitle("Stream Processor and Anomaly Detector Execution times")
#plt.title("From " + min_date.strftime('%Y-%m-%d %H:%M:%S') + " to "
#          + max_date.strftime('%Y-%m-%d %H:%M:%S'))

plt.xlabel(
    "Time",
    fontdict={
        'family': 'monospace',
        'color': 'xkcd:black',
        'weight': 'normal',
        'size': 14,
    },
    labelpad=6
)
plt.ylabel(
    "Delays (ms)",
    fontdict={
        'family': 'monospace',
        'color': 'xkcd:black',
        'weight': 'normal',
        'size': 14,
    },
    labelpad=6
)

[t.set_color('red') for t in ax.xaxis.get_ticklines()]
[t.set_color('red') for t in ax.xaxis.get_ticklabels()]

# vertical range for values (0 to configured MAX_Y)
plt.ylim((0, 50))

plt.grid(True, axis='y', alpha=0.5)

plt.axhline(y=10, color='r', linestyle='-')

plt.show()
plt.close(fig)

这需要 TestData.csv: https://www.toptal.com/developers/hastebin/uqepujujav.apache

它产生以下输出：

如您所见，只有我在代码中设置的 xtick 标签是红色的。不需要的（11:30、11:45 和 12:15）不受颜色影响。它们也不受我移除它们的所有尝试的影响。（我尝试了 ax.set_xticks([])、ax.set_xticklabels([])、plt.xticks([])、ax.xaxis.set_major_locator(ticker.NullLocator())）。

有什么想法吗？我失去了摆脱这些标签的希望。

Answer 1

通过使用 pandas 绘制日期作为 x-axis，自动设置 AutoDateLocator 和 AutoDateFormatter。这些设置自己的刻度，独立于 set_xticks（并且在缩放时也会计算新的刻度）。另见 matplotlib's date tick tutorial。

如示例中所示, pandas plotting doesn't work easy with customized date formatting。您可以直接通过 matplotlib 绘图。这是代码的可能改编：

import matplotlib.pyplot as plt
from matplotlib.dates import MinuteLocator, ConciseDateFormatter
import pandas as pd
import datetime as dt

data = pd.read_csv('TestData.csv', parse_dates=True)
data["datetime"] = data["datetime"].transform(lambda d: dt.datetime.strptime(d, '%Y-%m-%d %H:%M:%S'))
data.set_index("datetime")

fig, ax = plt.subplots(figsize=[24, 12], dpi=300)
ax.plot("datetime", "totalAIAD", data=data, color="xkcd:aquamarine")

locator = MinuteLocator(interval=5)
formatter = ConciseDateFormatter(locator)
formatter.formats = ['%y',  # ticks are mostly years
                     '%b',  # ticks are mostly months
                     '%d',  # ticks are mostly days
                     '%H:%M',  # hrs
                     '%H:%M:%S',  # min
                     '%S.%f', ]  # secs
formatter.zero_formats = [''] * len(formatter.formats)
formatter.offset_formats = [''] * len(formatter.formats) # this would write out the current date at the lower right
ax.xaxis.set_major_locator(locator)
ax.xaxis.set_major_formatter(formatter)

ax.set_xlabel("Time", fontdict={'family': 'monospace', 'color': 'xkcd:black', 'weight': 'normal', 'size': 14},
              labelpad=6)
ax.set_ylabel("Delays (ms)", fontdict={'family': 'monospace', 'color': 'xkcd:black', 'weight': 'normal', 'size': 14},
              labelpad=6)

[t.set_color('red') for t in ax.xaxis.get_ticklines()]
[t.set_color('red') for t in ax.xaxis.get_ticklabels()]

ax.set_ylim((0, 50))
ax.margins(x=0)
ax.grid(True, axis='y', alpha=0.5)
ax.axhline(y=10, color='r', linestyle='-')
fig.autofmt_xdate() # automatically makes the x-labels rotate
plt.tight_layout()
plt.show()

Matplotlib 显示额外的 x 标签集与常规 x 标签重叠

Matplotlib shows extra set of x labels overlapping regular x labels

python

datetime

timestamp

matplotlib

pandas