3.13 mcount - Count the Number of Rows

Count the number of rows and store the results in a new column defined in a= parameter. Counting is carried out by each aggregate key when k= parameter is specified. Otherwise, if k= is not specified, all rows are counted.

Format

mcount a= [k=] [i=] [o=] [-nfn] [-nfno] [-x] [-q] [--help] [--version]

Parameters

a=

Specify the new field name to be added.

 

This parameter is not required when nfn option is specified.

k=

Key item(s) (Multiple keys can be specified) [aggregate key break processing]

 

Count the number of instances for incremental rows based on the key field(s) defined.

Examples

Example 1: Basic Example

Count the number of rows by date, and save the results in a new column count.

$ more dat1.csv
date
20090109
20090109
20090109
20090110
20090110
$ mcount k=date a=count i=dat1.csv o=rsl1.csv
#END# kgcount a=count i=dat1.csv k=date o=rsl1.csv
$ more rsl1.csv
date%0,count
20090109,3
20090110,2

Example 2: Count without aggregate key

Count the number of rows without specifying the aggregate key.

$ mcount a=count i=dat1.csv o=rsl2.csv
#END# kgcount a=count i=dat1.csv o=rsl2.csv
$ more rsl2.csv
date,count
20090110,5

Related command

mstats : Specify c=count to count non-null values in the data.