SyntaxError：python 函数中的语法无效

Question

I don't see the issue in the function, I hope you can shed some light to the issue below. Thanks in advance.

Python function:

def gen_histograms(dataframe, cols=1, file=None):
    rows      = math.ceil(len(dataframe.columns)/cols)
    figwidth  = 5 * cols
    figheight = 4 * rows

    fig, ax = plt.subplots(nrows   = rows,
                           ncols   = cols,
                           figsize = (figwidth, figheight))

    color_choices = ['blue', 'grey', 'goldenrod', 'r', 'black', 'darkorange', 'g']
    ax = ax.ravel()         # Ravel turns a matrix into a vector... easier to iterate

    for i, column in enumerate(dataframe.columns):
        ax[i].hist(dataframe[column],
                      color=color_choices[i % len(color_choices)],
                      alpha = 1)

        ax[i].set_title(f'{dataframe[column].name}', fontsize=18)
        ax[i].set_ylabel('Observations', fontsize=14)
        ax[i].set_xlabel('', fontsize=14)

    fig.suptitle('\nHistograms for All Variables in Dataframe', size=24)
    fig.tight_layout()
    fig.subplots_adjust(bottom=0, top=0.88)
    if file: plt.savefig(file, bbox_inches='tight')
    plt.show();

    return

Error:

  File "<ipython-input-89-e68c3f9fb7c6>", line 24
    ax[i].set_title(f'{dataframe[column].name}', fontsize=18)
                                              ^
SyntaxError: invalid syntax

Answer 1

As suggested by @Ryan Haining, I've revised the working code.

def gen_histograms(dataframe, cols=1, file=None):
    rows      = math.ceil(len(dataframe.columns)/cols)
    figwidth  = 5 * cols
    figheight = 4 * rows

    fig, ax = plt.subplots(nrows   = rows,
                           ncols   = cols,
                           figsize = (figwidth, figheight))

    color_choices = ['blue', 'grey', 'goldenrod', 'r', 'black', 'darkorange', 'g']
    ax = ax.ravel()         # Ravel turns a matrix into a vector... easier to iterate

    for i, column in enumerate(dataframe.columns):
        ax[i].hist(dataframe[column],
                      color=color_choices[i % len(color_choices)],
                      alpha = 1)

        ax[i].set_title(dataframe[column].name, fontsize=18)
        ax[i].set_ylabel('Observations', fontsize=14)
        ax[i].set_xlabel('', fontsize=14)

    fig.suptitle('\nHistograms for All Variables in Dataframe', size=24)
    fig.tight_layout()
    fig.subplots_adjust(bottom=0, top=0.88)
    if file: plt.savefig(file, bbox_inches='tight')
    plt.show();

    return