Category: SPSS
How to change column names of Pandas DataFrames
There are 2 methods of changing the column names of Pandas Dataframes. The following shows the basic Python code syntax for changing column names of Pandas Dataframes. Method 1: df.rename(columns={‘old_name_1′:’new_name_1’, ‘old_name_2′:’new_name_2’}, inplace=True) Method 2: df = df.rename({‘old_name_1′:’new_name_1’, ‘old_name_2′:’new_name_2’}, axis=1) Example...
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Combine Lists into an Array in Python
You can use Numpy column_stack() or row_stack() to combine lists into an array. As Columns: np.column_stack((list1, list2,…)) As Rows: np.row_stack((list1, list2,…)) Example 1 of lists to columns The following combines lists into an array using column_stack(). Thus, lists become columns...
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Check if an item in a Python list
This tutorial shows examples of checking if an item is in a Python list. Method 1: item in list_name Method 2: list_name.index(item) Method 3: list_name.count(item) Example for method 1: Check if an item in a list The following code checks...
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Count the Number of NaN in Pandas Dataframes
This tutorial uses 2 examples to show how to count the number of NaN in Pandas dataframes. Method 1: count the number of NaN by columns: df.isnull().sum() Method 2: count the number of NaN in the whole dataframe: df.isnull().sum().sum() Example...
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How to Subset Rows in Pandas Dataframes
There are at least 4 methods to subset row in Pandas dataframes. Method 1: loc[[Comma]] df.loc[[row_number1, row_number_2]] Method 2: loc[Colon] df.loc[row_number1: row_number_2] Method 3: iloc[[Comma]] df.iloc[[row_number1, row_number_2]] Method 4: iloc[Colon] df.iloc[[row_number1: row_number_2]] Example 1 for Method 1 The following uses...
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Check if Any Value is NaN in a DataFrame
You can check if any value is NaN in a dataframe in Pandas in Python by using the following 2 methods. Method 1: check if any value is NaN by columns: df.isnull().any() Method 2: Check if any value is NaN...
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How to Replace NaN with Blank/Empty Cells in Pandas
You can replace NaN with Blank/Empty cells using either fillna() or replace() in Python. Single Column: Method 1: df[‘Column_name’].fillna(' ') Method 2: df[‘Column_name’].replace(np.nan,' ', regex=True) Whole dataframe: Method 1: df.fillna(' ') Method 2: df.replace(np.nan, ' ', regex=True) Example 1: single column The following uses...
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Difference between NumPy Random and Python Random
NumPy Random is from NumPy, whereas Python Random is a module in Python. That is, Python random is NOT part of NumPy. This tutorial uses two examples to show the difference between NumPy Random and Python Random. Example 1 Python...
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Examples of random.seed( ) in Python
random.seed() function can help save the state of random functions. Thus, by using seed(), these random functions can generate the same numbers on multiple code executions. Example 1 Example 1 shows how to use random.seed() and how it impacts the...
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When to Use ddof=1 in np.std()
The following is the rule of using ddof in np.std() in Numpy. Rule 1: If you are calculating standard deviation for a sample, set ddof = 1 in np.std(). np.std(sample_name, ddof=1) Rule 2: If you are calculating standard deviation for...
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