About this deal
This could be useful information during data cleaning. It could also be useful if you’re building a machine learning model, since some model types will not tolerate missing values. Look at the code. df.shape is a @property that runs a DataFrame method calling len twice. df.shape?? pandas.DataFrame.value_counts # DataFrame. value_counts ( subset = None, normalize = False, sort = True, ascending = False, dropna = True ) [source] #
based to the answer that was given and some improvements this is my approach def PercentageMissin(Dataset): Now that we have missing values in our DataFrame, let’s apply the method with its default parameters and see how the results look: # Seeing value counts But we can see that several of the rows displayed have 13 or 14 non-missing values. In fact, the first row has only 14 values. That means that some of these rows have missing values. That might be okay, but maybe not, depending on what you’re doing.
In this section, you’ll learn how to apply the Pandas .value_counts() method to a Pandas column. For example, if you wanted to count the number of times each value appears in the Students column, you can simply apply the function onto that column. The numeric_only parameter enables you to force the count method to only return counts for numeric variables. So if your dataframe is named your_dataframe, you can use the code your_dataframe.count() to count the number of non-missing values in each of the columns.
I struggled with the same issue, made use of the solution provided above. You can actually designate any of the columns to count: df.groupby(['revenue','session','user_id'])['revenue'].count()In the next section, you’ll learn how to sort your Pandas frequency table. Sorting Your Pandas Frequency Table
Now we are ready to use value_counts function. Let begin with the basic application of the function. It seems silly to compare the performance of constant time operations, especially when the difference is on the level of "seriously, don't worry about it". But this seems to be a trend with other answers, so I'm doing the same for completeness. Now that we’ve looked at the syntax, let’s look at some examples of how to use the Pandas count technique.
Use df.groupby(['Courses','Duration']).size().groupby(level=1).max() to specify which level you want as output. Note that the level starts from zero. Note that by default groupby sorts results by group key hence, it will take additional time, if you have a performance issue and don’t want to sort the group by the result, you can turn this off by using the sort=False param. In this post, you learned how to count the rows in a Pandas Dataframe. Specifically, you learned which methods are fastest, as well as how to count the number of rows in a dataframe containing a value, meeting a condition, and number of rows in different groups.
