csv is a tool that manipulates csv data and outputs the results to stdout.
to build: g++ -std=c++11 main.cpp -o csv
NOTE:
Tested with:
-Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) -Target: x86_64-apple-darwin14.1.0
usage: cat file.csv | ./csv where may include any/all of: -cols n_1 n_2 n_3 n_4 (where n_{1,2,3,4} are valid column indices) -addcol col_expr where col_expr is an expression consisting of: -colN where N is the column index -N where N is some integer -OP where OP is a binary operator from {+, *, -, /} -aggcol N {avg,med,min,max} where N is a valid column index avg - get average over column N med - get the median over column N min - get the min over column N max - get the max over column N -innerjoin, -outerjoin N file.csv where N is a column index and file.csv is a csv file (inner or outer) join the rows from stdin with the rows in file.csv. Joined rows' columns can be referenced in -aggcol,-addcol,and -cols expressions.
NOTE: This command line tool expects csv input from stdin, so this documentation expects that you are running it on a UNIX-like system where 'a | b' means send std out from 'a' to stdin of 'b'.
examples:
simplest example
$ cat small_data.csv | ./csv | 31 | 24 | 81 | 94 | | 22 | 46 | 35 | 57 | | 80 | 8 | 39 | 92 | | 65 | 67 | 57 | 46 | | 78 | 76 | 5 | 63 | | 31 | 68 | 95 | 29 | | 31 | 42 | 27 | 22 | | 12 | 41 | 74 | 91 | | 12 | 71 | 13 | 63 | ...
here's a projection
$ cat small_data.csv | ./csv -cols 1 3 | 24 | 94 | | 46 | 57 | | 8 | 92 | | 67 | 46 | | 76 | 63 | | 68 | 29 | | 42 | 22 | | 41 | 91 | | 71 | 63 | ...
here's a column expression
$ cat small_data.csv | ./csv -addcol col1+col2 | 31 | 24 | 81 | 94 | 105 | 105 | | 22 | 46 | 35 | 57 | 81 | 81 | | 80 | 8 | 39 | 92 | 47 | 47 | | 65 | 67 | 57 | 46 | 124 | 124 | | 78 | 76 | 5 | 63 | 81 | 81 | | 31 | 68 | 95 | 29 | 163 | 163 | | 31 | 42 | 27 | 22 | 69 | 69 | | 12 | 41 | 74 | 91 | 115 | 115 | | 12 | 71 | 13 | 63 | 84 | 84 | | 55 | 100 | 47 | 96 | 147 | 147 | ...
Here we redirect to stderr to /dev/null because warnings are emitted if a null column is used in an expression
$ cat small_data.csv | ./csv -outerjoin 1 more_small_data.csv -addcol col1+col2 2>/dev/null | 31 | 24 | 81 | 94 | 105 |105 | | 22 | 46 | 35 | 57 | 81 | 70 | 46 | 99 | 33 | 81 | | 22 | 46 | 35 | 57 | 81 | 63 | 46 | 68 | 52 | 81 | | 22 | 46 | 35 | 57 | 81 | 84 | 46 | 17 | 83 | 81 | | 80 | 8 | 39 | 92 | 47 | 13 | 8 | 39 | 14 | 47 | | 65 | 67 | 57 | 46 | 124 | 9 | 67 | 13 | 9 | 124 | | 65 | 67 | 57 | 46 | 124 | 47 | 67 | 16 | 24 | 124 | | 65 | 67 | 57 | 46 | 124 | 28 | 67 | 32 | 27 | 124 | | 78 | 76 | 5 | 63 | 81 | 75 | 76 | 38 | 87 | 81 | | 78 | 76 | 5 | 63 | 81 | 89 | 76 | 5 | 97 | 81 | | 78 | 76 | 5 | 63 | 81 | 41 | 76 | 31 | 23 | 81 | | 31 | 68 | 95 | 29 | 163 |163 | | 31 | 42 | 27 | 22 | 69 | 96 | 42 | 7 | 27 | 69 | | 31 | 42 | 27 | 22 | 69 | 4 | 42 | 75 | 48 | 69 | | 31 | 42 | 27 | 22 | 69 | 97 | 42 | 19 | 59 | 69 | | 31 | 42 | 27 | 22 | 69 | 9 | 42 | 31 | 22 | 69 | | 12 | 41 | 74 | 91 | 115 | 2 | 41 | 54 | 81 | 115 | | 12 | 41 | 74 | 91 | 115 | 85 | 41 | 76 | 50 | 115 | | 12 | 41 | 74 | 91 | 115 | 11 | 41 | 18 | 43 | 115 | | 12 | 71 | 13 | 63 | 84 | 84 | ... | | | | | | 63 | 46 | 68 | 52 | <------------ NULL columns 1 and 2 | | | | | | 85 | 41 | 76 | 50 | | | | | | | 59 | 64 | 55 | 6 | | | | | | | 47 | 67 | 16 | 24 | | | | | | | 8 | 34 | 55 | 36 | | | | | | | 38 | 21 | 45 | 39 | | | | | | | 75 | 36 | 29 | 96 | | | | | | | 22 | 98 | 22 | 87 | | | | | | | 28 | 95 | 37 | 75 | | | | | | | 94 | 52 | 81 | 3 | | | | | | | 93 | 56 | 66 | 90 | | | | | | | 46 | 50 | 41 | 1 | ...
And finally an aggregate:
$ cat small_data.csv | ./csv -aggcol avg 9 -outerjoin 1 more_small_data.csv -addcol col1+col2 | | | | | | 28 | 38 | 30 | 64 | | | | | | | 65 | 14 | 70 | 61 | | | | | | | 41 | 76 | 31 | 23 | | | | | | | 69 | 98 | 42 | 89 | | | | | | | 14 | 15 | 89 | 36 | avg: 91