python runtime_error ai_generated true

ValueError: No figure with number 1 exists

ID: python/matplotlib-savefig-no-fignum

Also available as: JSON · Markdown · 中文
80%Fix Rate
85%Confidence
0Evidence
2024-10-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.x active — — —

Root Cause

Calling plt.figure(1) or plt.savefig on a figure number that was closed (plt.close('all')) or never created.

generic

中文

调用了 plt.figure(1) 或对已关闭（plt.close('all')）或从未创建的图形编号调用 plt.savefig。

Workarounds

  1. 96% success 
    fig = plt.figure(num=1, figsize=(6,4))
ax = fig.add_subplot(111)
ax.plot([1,2,3])
fig.savefig('out.png')
  2. 97% success 
    fig, ax = plt.subplots()
ax.plot([1,2,3])
fig.savefig('out.png')  # never rely on figure numbers

Dead Ends

Common approaches that don't work:

  1. 85% fail

    The figure genuinely does not exist; subsequent savefig calls will still fail.

  2. 80% fail

    draw() only redraws existing figures; it does not create one with a given number.