read_csv

Builtin index · File I/O

result = read_csv(path, [headers=true], [sep=","], [decimal="."])

Input: path, headers, sep, decimal · Output: result

What it is

Reads a CSV file into a Table. path (string) is the file to read. headers (boolean, optional, default true) — false treats the first line as data instead of column names (columns are then auto-named col1, col2, ...). sep (string, optional, default ",") is the field delimiter. decimal (string, optional, default ".") is the decimal-point marker (e.g. sep=";", decimal="," for the European convention).

Overloads

One call shape — this function is not overloaded.

Examples

From the documentation, and run by the build -- the output and the figure below are what the engine actually produced. Simplest first.

t = read_csv(path, headers = true)
print("rows: {nrow(t)}")
print(head(t, 2))

from agent-guide

write_csv(df, "data.csv")
df2 = read_csv("data.csv")
print(df2)
table.write(df, "data2.csv")
df3 = table.load("data2.csv")
print(df3)

x   y
-  --
1  10
2  20
3  -5
x   y
-  --
1  10
2  20
3  -5

from tour

function load_and_process(path)
    profiling_mode(true)
    data = read_csv(path, headers=true)
    result = data.sort_by("value")
    profiling_mode(false)
    print(profile_stats())     # a real Table: function / calls / seconds


    sandbox_mode(true)
    try
        touch("audit.log")     # denied -- sandboxed for this section only

    catch err
        print("blocked: {err.message}")
    end
    sandbox_mode(false)

    return result
end function

from quickstart

measurements = table(
    x = [-1.5, 0.5, 2.0, -0.25, 3.75],
    sensor = ["a", "b", "a", "c", "b"]
)
write_csv(measurements, "measurements.csv")

df = read_csv("measurements.csv")
print(nrow(df))
print(describe(df))
write_csv(filter(df, df.x > 0), "positive_only.csv")
print(read_all_text("positive_only.csv"))

5
stat         x
-----  -------
count        5
mean       0.9
std    2.03562
min       -1.5
25%      -0.25
50%        0.5
75%          2
max       3.75
x,sensor
0.5,b
2,a
    ... 1 more lines

from file-io

How it works

read_csv(path, [headers=], [sep=], [decimal=]) — headers (default true) treats the first line as data instead of column names when false (columns auto-named col1, col2, ...); sep (default ",") is the field delimiter; decimal (default ".") is the decimal-point marker ("," for the European convention). See Table::from_csv_opts's own doc comment for the motivating sep=";" + decimal="," case and why there's no implicit per-field decimal auto-detection.

From the note above this builtin in the interpreter, where the reasoning was written down as it was built.