pandas - Read For Learn

Truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all()

The or and and python statements require truth-values. For pandas these are considered ambiguous so you should use “bitwise” | (or) or & (and) operations: These are overloaded for these kind of datastructures to yield the element-wise or (or and). Just to add some more explanation to this statement: The exception is thrown when you want to get the bool of a pandas.Series: What you hit was a place where the operator implicitly converted … Read more

Selecting multiple columns in a Pandas dataframe

The column names (which are strings) cannot be sliced in the manner you tried. Here you have a couple of options. If you know from context which variables you want to slice out, you can just return a view of only those columns by passing a list into the __getitem__ syntax (the []’s). Alternatively, if … Read more

Reading an Excel file in python using pandas

Close: first you call ExcelFile, but then you call the .parse method and pass it the sheet name. What you’re doing is calling the method which lives on the class itself, rather than the instance, which is okay (although not very idiomatic), but if you’re doing that you would also need to pass the sheet … Read more

Writing a pandas DataFrame to CSV file

To delimit by a tab you can use the sep argument of to_csv: To use a specific encoding (e.g. ‘utf-8’) use the encoding argument:

How to iterate over rows in a DataFrame in Pandas

DataFrame.iterrows is a generator which yields both the index and row (as a Series):

pandas read_json: “If using all scalar values, you must pass an index”

Try That file only contains key value pairs where values are scalars. You can convert it to a dataframe with ser.to_frame(‘count’). You can also do something like this: Now data is a dictionary. You can pass it to a dataframe constructor like this:

How to iterate over rows in a DataFrame in Pandas

DataFrame.iterrows is a generator which yields both the index and row (as a Series):

Constructing pandas DataFrame from values in variables gives “ValueError: If using all scalar values, you must pass an index”

The error message says that if you’re passing scalar values, you have to pass an index. So you can either not use scalar values for the columns — e.g. use a list: or use scalar values and pass an index:

How to deal with SettingWithCopyWarning in Pandas

The SettingWithCopyWarning was created to flag potentially confusing “chained” assignments, such as the following, which does not always work as expected, particularly when the first selection returns a copy. [see GH5390 and GH5597 for background discussion.] The warning offers a suggestion to rewrite as follows: However, this doesn’t fit your usage, which is equivalent to: While it’s clear that you don’t care … Read more

How to deal with SettingWithCopyWarning in Pandas

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