What is the essence of the {0} when Cleaning Data/Reading Data

Question

I am trying to read data and I cannot understand what the {0} should be doing when reading the file. What is the purpose of it?

data_files = [
    "ap_2010.csv",
    "class_size.csv",
    "demographics.csv",
    "graduation.csv",
    "hs_directory.csv",
    "sat_results.csv"
]
data = {}

for file in data_files:
    dataframe= pd.read_csv('schools/{0}'.format(file))
    dataframe_name = file.replace(".csv","")
    data[dataframe_name] = dataframe```

See [str.format](https://docs.python.org/3/library/stdtypes.html#str.format). You are passing the 0th argument (`file` in your example) to `{0}` — not_speshal, Jul 07 '21 at 17:57
Does this answer your question? [String formatting in Python](https://stackoverflow.com/questions/517355/string-formatting-in-python) — buran, Jul 07 '21 at 17:57
also this is NOT proper way to construct path. you should use `pathlib` or `os.path.join()` — buran, Jul 07 '21 at 17:59
Also, which python interpreter _are you actually using_: 2 or 3? (Don't use both tags 'just because'.) — msanford, Jul 07 '21 at 17:59

score 1 · Answer 1 · answered Jul 07 '21 at 18:00

It's a way to link the list of values you're passing in the format() method to their place in the string. The {0} says it should be replaced by the first value on the format method. This means that you will end up with a 'schools/file'.

If you had another value like file format (csv, json, parquet) you could use:

"schools/{0}.{1}".format(file, format)

To get what you want.

score 0 · Answer 2 · answered Jul 07 '21 at 17:57

It's a positional argument to str.format():

Perform a string formatting operation. The string on which this method is called can contain literal text or replacement fields delimited by braces {}. Each replacement field contains either the numeric index of a positional argument, or the name of a keyword argument. Returns a copy of the string where each replacement field is replaced with the string value of the corresponding argument.

What is the essence of the {0} when Cleaning Data/Reading Data

2 Answers2