R. How to count row numbers by condition and put into new column
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Add column with counts of another
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unique combinations of values in selected columns in pandas data frame and count
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Adding counts of a factor to a dataframe
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Conditional summing (R)
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How to split numbers into columns with negative and positive values, without empty cells?
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Add (insert) a column between two columns in a data.frame
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Using R statistics add a group sum to each row
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How do I use plyr to number rows?
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Counting existing permutations in R
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Assigning row number for sorted table by column in QGIS
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Transpose N rows with different columns into single column
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Copy value from Lookup (CountRelated) column to another 'Number' column
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error in count script for number of occurences
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Counting unique addresses from a list in column A if criteria for column B is met
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python - Count number of occurrences of each number
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How to sort a character vector where elements contain letters and numbers in R?
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How can I remove all duplicates so that NONE are left in a data frame?