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Pandas read_excel: only read first few lines #16645

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vfridkin opened this Issue Jun 9, 2017 · 5 comments

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@vfridkin
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commented Jun 9, 2017

Code Sample, a copy-pastable example if possible

workbook_dataframe = pd.read_excel(workbook_filename, nrows = 10)

Problem description

Using pandas read_excel on about 100 excel files - some are large - I want to read the first few lines of each (header and first few rows of data).

The above doesn't work but illustrates the goal (example reading 10 data rows).

@chris-b1

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commented Jun 9, 2017

Sure, could support this, although xlrd (library we use to read Excel files) always reads the whole file into memory, so it wouldn't be as fast as you'd hope.

@chris-b1 chris-b1 added this to the Next Major Release milestone Jun 9, 2017

@alysivji

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commented Jun 10, 2017

I'm looking into adding this functionality. Thanks.

@alysivji alysivji referenced this issue Jun 11, 2017

Closed

Read excel nrows #16672

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@ppritish51

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commented Jun 25, 2017

You can add one line in your code below where you are reading your file. For example, if you want to read first 10 rows of the file then you can do this.

workbook_dataframe = pd.read_excel(workbook_filename)
workbook_dataframe =workbook_dataframe.iloc[:10]

or even you can simply do this
workbook_dataframe = pd.read_excel(workbook_filename).iloc[:10]

so that your data frame now contains only first 10 rows.

@gmlander

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commented Sep 25, 2017

To get nrows without reading the entire worksheet:

workbook = pd.ExcelFile(workbook_filename)

# get the total number of rows (assuming you're dealing with the first sheet)
rows = workbook.book.sheet_by_index(0).nrows

# define how many rows to read
nrows = 10

# subtract the number of rows to read from the total number of rows (and another 1 for the header)
workbook_dataframe = pd.read_excel(workbook, skip_footer = (rows - nrows - 1))
@Ellest

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commented Nov 12, 2017

Could I take a crack at this issue? I'm new to open source and would really like to start contributing. If the last line in @gmlander 's code is valid, I'd just have to identify where to place the code right? Thanks for any suggestions in advance!

@alysivji alysivji referenced this issue Nov 26, 2017

Merged

Add nrows parameter to pandas.read_excel() #18507

4 of 4 tasks complete

@jreback jreback modified the milestones: Next Major Release, 0.22.0 Dec 3, 2017

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