Delimited Files

The goal of reading and writing throughout TidierFiles.jl is to use consistent syntax. This functions on this page focus on delimited files and are powered by CSV.jl.

using TidierFiles

read_csv/tsv/delim

read_csv("https://raw.githubusercontent.com/TidierOrg/TidierFiles.jl/main/testing_files/csvtest.csv", skip = 2, n_max = 3, col_select = ["ID", "Score"], missing_value = ["4"])

#read_csv(file; delim=',', col_names=true, skip=0, n_max=Inf, comment=nothing, missing_value="", col_select=nothing, escape_double=true, col_types=nothing, num_threads=1)

#read_tsv(file; delim='\t', col_names=true, skip=0, n_max=Inf, comment=nothing, missing_value="", col_select=nothing, escape_double=true, col_types=nothing, num_threads=Threads.nthreads())

#read_delim(file; delim='\t', decimal = '.', groupmark = nothing col_names=true, skip=0, n_max=Inf, comment=nothing, missing_value="", col_select=nothing, escape_double=true, col_types=nothing, num_threads=Threads.nthreads())

#read_csv2(file; delim=';', decimal = ',', col_names=true, skip=0, n_max=Inf, comment=nothing, missing_value="", col_select=nothing, escape_double=true, col_types=nothing, num_threads=Threads.nthreads())

#These functions read a delimited file (CSV, TSV, or custom delimiter) into a DataFrame. The arguments are:

3×2 DataFrame

Row	ID	Score
	Int64?	Int64
1	3	77
2	missing	85
3	5	95

• file: Path or vector of paths to the file(s) or a URL(s).
• delim: Field delimiter. Default is ',' for read_csv, '\t' for read_tsv and read_delim.
• col_names: Use first row as column names. Can be true, false, or an array of strings. Default is true.
• skip: Number of lines to skip before reading data. Default is 0.
• n_max: Maximum number of rows to read. Default is Inf (read all rows).
• comment: Character indicating comment lines to ignore. Default is nothing.
• missing_value: String(s) representing missing values. Default is "".
• col_select: Optional vector of symbols or strings to select columns to load. Default is nothing.
• groupmark: A symbol that separates groups of digits Default is nothing.
• decimal: An ASCII Char argument that is used when parsing float values. Default is '.'.
• escape_double: Interpret two consecutive quote characters as a single quote. Default is true.
• col_types: Optional specification of column types using a Dict. Default is nothing (types are inferred).
• num_threads: Number of threads to use for parallel execution. Default is 1 for read_csv and the number of available threads for read_tsv and read_delim.
• kwarg: any CSV.jl argument can be passed to any of the above functions with correct syntax, and it will be supported.

The functions return a DataFrame containing the parsed data from the file.

write_csv and write_tsv

writecsv(x, file; missingvalue="", append=false, colnames=true, eol="\n", numthreads=Threads.nthreads())

writetsv(x, file; missingvalue="", append=false, colnames=true, eol="\n", numthreads=Threads.nthreads())

These functions write a DataFrame to a CSV or TSV file. The arguments are:

• x: The DataFrame to write.
• file: The path to the output file.
• missing_value: The string to represent missing values. Default is an empty string.
• append: Whether to append to an existing file. Default is false.
• col_names: Whether to write column names as the first line. Default is true.
• eol: The end-of-line character. Default is "\n".
• num_threads: The number of threads to use for writing. Default is the number of available threads.

read_table

readtable(file; colnames=true, skip=0, nmax=Inf, comment=nothing, colselect=nothing, missingvalue="", numthreads)

This function reads a table from a whitespace-delimited file into a DataFrame. The arguments are:

• file: The path to the file to read.
• col_names: Whether the first non-skipped line contains column names. Default is true.
• skip: Number of lines to skip before processing. Default is 0.
• n_max: Maximum number of lines to read. Default is Inf (read all lines).
• comment: Character or string indicating comment lines to ignore. Default is nothing.
• col_select: Optional vector of symbols or strings to select columns to load. Default is nothing.
• missing_value: The string representing missing values. Default is "".
• num_threads: The number of threads to use for writing. Default is the number of available threads.

write_table

writetable(x, file; delim='\t', missingvalue="", append=false, colnames=true, eol="\n", numthreads=Threads.nthreads())

This function writes a DataFrame to a file with customizable delimiter and options. The arguments are:

• x: The DataFrame to write.
• file: The path to the output file.
• delim: The field delimiter. Default is '\t' (tab-separated).
• missing_value: The string to represent missing values. Default is "".
• append: Whether to append to an existing file. Default is false.
• col_names: Whether to write column names as the first line. Default is true.
• eol: The end-of-line character. Default is "\n".
• num_threads: The number of threads to use for writing. Default is the number of available threads.

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