The Filer Class¶

class helpers.filer.Filer(path: pathlib.Path, create: bool = True, delimiter: str = '\t')¶

Bases: object

A class for gracefully handling file interactions with delimited data

Designed particularly for passing context in a CLI, it is a thin wrapper for many common file I/O actions, including reading, writing (both lines and columns), and deleting.

append(rows: List[List[str]]) → None¶

Appends contents of rows to self.path

Note

This will not over-write the contents of the file, mirroring the modes of open()

Parameters: rows (List[List[str]]) – A list of strings to write to self.path.
Returns: None

Examples

>>> example.append([['f','g', 'h'], ['i', 'j', 'k']])

delete(contains: str) → bool¶

Deletes all lines from self where contains in line

Parameters: contains (str) – String to match for line deletion
Returns: bool – True if successulf, false otherwise

Example

>>> example.delete('j')
True

read() → List[List[str]]¶

Read the lines of self.path

Note

Reads in all lines, so will suffer on large files

Parameters: None
Returns: List[List[str]] – A list of lines where each line is a list of column values

Examples

>>> example.read()
[['ID', 'Rank', 'Date', 'Task'], ['f', 'g', 'h']]

sort(cols: List[int], header: bool = False) → None¶

Sort the contents of self.path by columns

Parameters

cols (List[int]) – List of column indices indicating what to sort by. Remember, Python is 0-indexed
header (bool) – Whether or not row 0 is a header. If True, row 0 is skipped for sorting

Returns

None

Example

>>> example.sort([1, 2], header=False)

write(rows: List[List[str]]) → None¶

Writes contents of rows to self.path.

Warning

If the file already has content, that will be overwritten! This mirrors the modes used by open()

Parameters: rows (List[List[str]]) – A list of strings to write to self.path. rows[0] represents line 1, and rows[0][0] is line 1, column 1.
Returns: None

Examples

>>> example.write([['a', 'b', 'c']])

write_col(col: List[str], index: int = 0) → None¶

Writes contents of col to self.path at specified index

Warning

If the column already has content, that will be overwritten! This mirrors the modes used by open()

Parameters

col (List[str]) – A list of strings to write to self.path. This should be the same length as self.length
index (int) – Which column to write at. Remember, Python is 0-indexed.

Returns

None

Raises

IndexError – When col has more or less items than self.length

Examples

>>> example.write_col(['d'], index=2)