python - Matplotlib : Can't create log plots

Question

我正在遍历数据框的每一列并尝试将对数图创建为

cols = in_df.columns

for col in cols:
    in_df[col]=in_df[col].dropna()
    print (in_df[col].values)
    in_df[col].map(np.log).hist(bins=1000)
    plt.xlabel(x_label+col)
    plt.ylabel('Number of customers in train')
    plt.savefig(save_dir+col+'.png')
    plt.close()

但我收到以下错误:

[2 2 2 ..., 2 2 2]
in_df[col].map(np.log).hist(bins=1000)
 File "anaconda/envs/kaggle3/lib/python3.5/site-packages/pandas/tools/plotting.py", line 2988, in hist_series
    ax.hist(values, bins=bins, **kwds)
  File "anaconda/envs/kaggle3/lib/python3.5/site-packages/matplotlib/__init__.py", line 1819, in inner
    return func(ax, *args, **kwargs)
  File "anaconda/envs/kaggle3/lib/python3.5/site-packages/matplotlib/axes/_axes.py", line 5985, in hist
    m, bins = np.histogram(x[i], bins, weights=w[i], **hist_kwargs)
  File "anaconda/envs/kaggle3/lib/python3.5/site-packages/numpy/lib/function_base.py", line 505, in histogram
    'range parameter must be finite.')
ValueError: range parameter must be finite.

请注意以下工作:

in_df.col_name.map(np.log).hist(bins=1000)

但是，我不能在遍历所有列时使用这种方法。知道我为什么会收到错误吗？

Answer 1

如果我对零的看法是正确的，那么解决问题的最简单方法就是删除它们。有很多方法可以做到这一点。下面是一个:

cols = in_df.columns

for col in cols:
    in_df[col]=in_df[col].dropna()
    print (in_df[col].values)
    # I edited line below
    in_df[col].replace(0, np.nan).dropna().map(np.log).hist(bins=1000)
    # added   |<------------------------>|
    plt.xlabel(x_label+col)
    plt.ylabel('Number of customers in train')
    plt.savefig(save_dir+col+'.png')
    plt.close()