## How to extract the row before the value of a column changes

excel extract all rows that contain a value

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I have dataframe as follows:

df=pd.DataFrame({'value':[3,4,7,8,11,20,15,20,15,16], 'ID':[2,2,8,8,8,2,2,2,5,5], 'distance':[0,0,1,0,0,0,2,0,0,0]}) print(df) value ID distance 0 3 2 0 1 4 2 0 2 7 8 1 3 8 8 0 4 11 8 0 5 20 2 0 6 15 2 2 7 20 2 0 8 15 5 0 9 16 5 0

I want to extract the row that occurs before the value changes from 0 to 1 in the column `distance`

.

From my sample dataframe I would expect the output to be as follows:

df_out=pd.DataFrame({'value':[4],'ID':[2],'distance':[0]}) print(df_out) value ID distance 0 4 2 0

I think you just need a slight change to Quang Hoang's second suggestion (the shift should be -1).

Like this: df.loc[df['distance'].eq(0) & df['distance'].shift(-1).eq(1)]

This means: [if distance at a row is 0, and if distance at row-1 is 1] which is what you want. It's result is:

value ID distance 1 4 2 0

The only difference with the expected output you wrote is that the index is kept (1), if you really want index reset then you can do so like this:

df[df['distance'].eq(0) & df['distance'].shift(-1).eq(1)].reset_index(drop=True)

which gives exactly what you wrote in your question:

value ID distance 0 4 2 0

You can look at the doc for info on shift

**Retrieve records when value in column changes,** ; WITH CTE AS ( SELECT [DATE], [NAME], LAG([NAME]) OVER (ORDER BY [ DATE]) AS [PREVIOUS] FROM myTable ) SELECT TOP 1 FROM (select row_number() over (partition by System order by Timestamp asc) as aRow, Timestamp, System, StatusA, StatusB from tableX) as a left join (select row_number() over (partition by System order by Timestamp asc) as bRow, Timestamp, System, StatusA, StatusB from tableX) as b on a.aRow = b.bRow + 1 and a.System = b.System where (a.StatusA

Hope this helps!

I am using an extra column `mask`

to shift the values of `distance`

. First I initialize the column to zero and then I update that columns with shifted values of `distance`

column

>>> df['mask'] = 0 >>> df['mask'][:-1] = df['distance'][1:] >>> df value ID distance mask 0 3 2 0 0 1 4 2 0 1 2 7 8 1 0 3 8 8 0 0 4 11 8 0 0 5 20 2 0 2 6 15 2 2 0 7 20 2 0 0 8 15 5 0 0 9 16 5 0 0 >>> df_out = df[['value', 'ID', 'distance']][df['mask'] == 1].reset_index(drop=True) >>> df_out value ID distance 0 4 2 0

This may not be the best solution but a working solution.

**How to Retrieve The Entire Row of a Matched Value,** In this article, we will learn how to retrieve the entire row of a matched value by using Vlookup Change ID in an existing cell or just add a new row with a new ID, all the data will be displayed until you have this formula referencing that ID cell. COLUMN function of excel returns column index number of a given cell. Count cells until value changes with formula. Here is a simple formula can help you to quickly count the number of cells until value changes. Select a blank cell next to the values you want to count, enter this formula =COUNTIF(A$1:A1,A1) and drag auto fill handle over the cells needed this formula.

Just check backward diff equal `-1`

and `distance`

equal `0`

m = df.distance.diff(-1).eq(-1) & df.distance.eq(0) df.loc[m] Out[635]: value ID distance 1 4 2 0

**Extract all rows from a range that meet criteria in one column,** Extract all rows from a range that meet criteria in one column D14 and D15), the formula lets you change the column to search in with cell D16. The image above shows filtered records based on two conditions, values in Hello! How do I access a specific row and column from a dataset and save it to a global variable for later use? for example from sashelp.cars dataset how do I get first row value for 'Make' column? %macro ExtractACell(rownum=1, VarName='Make'); data work.TempDelete; set sashelp.cars; if _

**Extract all rows that contain a value between this and that,** The picture above shows you the formula result in cell range B20:C25. Step 4 - Return value based on row and column number. The INDEX Then press F5 key to run this code, and a prompt box will pop out to let you select one column data that you want to insert blank rows when value changes which you based on, see screenshot: 4 . And then click OK , the blank rows have been inserted between data when the value changes based on column A.

**How to Use Values from Previous or Next Rows in a SQL Server Query,** In SQL Server versions prior to 2012, you need to perform a join to tell it what value to retrieve from a previous row (either a column or an For each row, the result from the AND function is added to the "value above" in the helper column to generate a count. The practical effect of this formula is an incrementing counter that only changes when a (new) match is found. Then the value remains the same until the next match is found.

**Mastering Data Warehouse Design: Relational and Dimensional Techniques,** The extract will always contain what has changed since the last extract or the impact of that change. Such an interface contains one row per column changed . for when the change occurred, and the before and after values for the column. Hi, I want to extract all the unique values from column A starting with A2 to the last cell of column A that has a value and copy those values into cell B2 all the way down to whatever the last cell of column B is. I have row titles in cells A1 and B1. Example: Data Before Macro

##### Comments

`df.loc[df['distance'].diff().eq(-1)]`

or`df.loc[df['distance'].eq(0) & df['distance'].shift().eq(1)]`

?- @QuangHoang row should be recorded when value change from 0 to 1 , any other change dont need to consider like you can see in my input when value changing from 0 to 2 i dont need to record row
- I think you just need a slight change to Quang Hoang's second suggestion (the shift should be -1). Like this:
`df.loc[df['distance'].eq(0) & df['distance'].shift(-1).eq(1)]`