Error ValueError: Number of columns must be a positive integer, not 0

ValueError Traceback (most recent call last)
<ipython-input-22-541b90fa47bc> in <cell line: 7>()
      5   return title[:10]
      6 
----> 7 fig, axs = plt.subplots(2, (len(app_infos)) // 2, figsize=(14, 5))
      8 
      9 for i, ax in enumerate(axs.flat):

4 frames
/usr/local/lib/python3.10/dist-packages/matplotlib/gridspec.py in __init__(self, nrows, ncols, height_ratios, width_ratios)
     50                 f"Number of rows must be a positive integer, not {nrows!r}")
     51         if not isinstance(ncols, Integral) or ncols <= 0:
---> 52             raise ValueError(
     53                 f"Number of columns must be a positive integer, not {ncols!r}")
     54         self._nrows, self._ncols = nrows, ncols

ValueError: Number of columns must be a positive integer, not 0

def format_title(title): sep_index = title.find(':') if title.find(':') != -1 else title.find('-') if sep_index != -1: title = title[:sep_index] return title[:10]

fig, axs = plt.subplots(2, (len(app_infos)) // 2, figsize=(14, 5))

for i, ax in enumerate(axs.flat): ai = app_infos[i] img = plt.imread(ai['icon']) ax.imshow(img) ax.set_title(format_title(ai['title'])) ax.axis('off')

The issue with your code appears to be due to the expression len(app_infos) // 2 resulting in zero. This will happen if app_infos is empty or has only one item. When you use the // operator (floor division), and the size of app_infos is either 1 or 0, the output is 0.

The exception message ValueError: Number of columns must be a positive integer, not 0 is indicating that your code is trying to create a subplot with 2 rows and 0 columns, which is not feasible.

Here's a refined version of your code to address this issue:

import matplotlib.pyplot as plt


def format_title(title):
    sep_index = title.find(':') if title.find(':') != -1 else title.find('-')
    if sep_index != -1:
        title = title[:sep_index]
    return title[:10]

# Ensuring at least 1 column for the subplots
columns = max(int(len(app_infos)//2), 1)

fig, axs = plt.subplots(2, columns, figsize=(14, 5))

for i, ax in enumerate(axs.flat):
    ai = app_infos[i]
    img = plt.imread(ai['icon'])
    ax.imshow(img)
    ax.set_title(format_title(ai['title']))
    ax.axis('off')

In the revised code, I've replaced len(app_infos) // 2 with max(int(len(app_infos)//2), 1) within plt.subplots. This modification ensures that the number of columns set for the subplot is always at least 1.

Side-Note

In the future, please provide a more detailed description of your problem and ensure that all necessary code components, such as the app_infos list, are included.