Python pandas库 DataFrame和Series类函数用法Help

Help on class StringMethods in module pandas.core.strings.accessor: class StringMethods(pandas.core.base.NoNewAttributesMixin) | StringMethods(data) | | Vectorized string functions for Series and Index. | | NAs stay NA unless handled otherwise by a particular method. | Patterned after Python's string methods, with some inspiration from | R's stringr package. | | Examples | -------- | >>> s = pd.Series(["A_Str_Series"]) | >>> s | 0 A_Str_Series | dtype: object | | >>> s.str.split("_") | 0 [A, Str, Series] | dtype: object | | >>> s.str.replace("_", "") | 0 AStrSeries | dtype: object | | Method resolution order: | StringMethods | pandas.core.base.NoNewAttributesMixin | builtins.object | | Methods defined here: | | __getitem__(self, key) | | __init__(self, data) | Initialize self. See help(type(self)) for accurate signature. | | __iter__(self) | | capitalize(self) | Convert strings in the Series/Index to be capitalized. | | Equivalent to :meth:`str.capitalize`. | | Returns | ------- | Series or Index of object | | See Also | -------- | Series.str.lower : Converts all characters to lowercase. | Series.str.upper : Converts all characters to uppercase. | Series.str.title : Converts first character of each word to uppercase and | remaining to lowercase. | Series.str.capitalize : Converts first character to uppercase and | remaining to lowercase. | Series.str.swapcase : Converts uppercase to lowercase and lowercase to | uppercase. | Series.str.casefold: Removes all case distinctions in the string. | | Examples | -------- | >>> s = pd.Series(['lower', 'CAPITALS', 'this is a sentence', 'SwApCaSe']) | >>> s | 0 lower | 1 CAPITALS | 2 this is a sentence | 3 SwApCaSe | dtype: object | | >>> s.str.lower() | 0 lower | 1 capitals | 2 this is a sentence | 3 swapcase | dtype: object | | >>> s.str.upper() | 0 LOWER | 1 CAPITALS | 2 THIS IS A SENTENCE | 3 SWAPCASE | dtype: object | | >>> s.str.title() | 0 Lower | 1 Capitals | 2 This Is A Sentence | 3 Swapcase | dtype: object | | >>> s.str.capitalize() | 0 Lower | 1 Capitals | 2 This is a sentence | 3 Swapcase | dtype: object | | >>> s.str.swapcase() | 0 LOWER | 1 capitals | 2 THIS IS A SENTENCE | 3 sWaPcAsE | dtype: object | | casefold(self) | Convert strings in the Series/Index to be casefolded. | | .. versionadded:: 0.25.0 | | Equivalent to :meth:`str.casefold`. | | Returns | ------- | Series or Index of object | | See Also | -------- | Series.str.lower : Converts all characters to lowercase. | Series.str.upper : Converts all characters to uppercase. | Series.str.title : Converts first character of each word to uppercase and | remaining to lowercase. | Series.str.capitalize : Converts first character to uppercase and | remaining to lowercase. | Series.str.swapcase : Converts uppercase to lowercase and lowercase to | uppercase. | Series.str.casefold: Removes all case distinctions in the string. | | Examples | -------- | >>> s = pd.Series(['lower', 'CAPITALS', 'this is a sentence', 'SwApCaSe']) | >>> s | 0 lower | 1 CAPITALS | 2 this is a sentence | 3 SwApCaSe | dtype: object | | >>> s.str.lower() | 0 lower | 1 capitals | 2 this is a sentence | 3 swapcase | dtype: object | | >>> s.str.upper() | 0 LOWER | 1 CAPITALS | 2 THIS IS A SENTENCE | 3 SWAPCASE | dtype: object | | >>> s.str.title() | 0 Lower | 1 Capitals | 2 This Is A Sentence | 3 Swapcase | dtype: object | | >>> s.str.capitalize() | 0 Lower | 1 Capitals | 2 This is a sentence | 3 Swapcase | dtype: object | | >>> s.str.swapcase() | 0 LOWER | 1 capitals | 2 THIS IS A SENTENCE | 3 sWaPcAsE | dtype: object | | cat(self, others=None, sep=None, na_rep=None, join='left') | Concatenate strings in the Series/Index with given separator. | | If `others` is specified, this function concatenates the Series/Index | and elements of `others` element-wise. | If `others` is not passed, then all values in the Series/Index are | concatenated into a single string with a given `sep`. | | Parameters | ---------- | others : Series, Index, DataFrame, np.ndarray or list-like | Series, Index, DataFrame, np.ndarray (one- or two-dimensional) and | other list-likes of strings must have the same length as the | calling Series/Index, with the exception of indexed objects (i.e. | Series/Index/DataFrame) if `join` is not None. | | If others is a list-like that contains a combination of Series, | Index or np.ndarray (1-dim), then all elements will be unpacked and | must satisfy the above criteria individually. | | If others is None, the method returns the concatenation of all | strings in the calling Series/Index. | sep : str, default '' | The separator between the different elements/columns. By default | the empty string `''` is used. | na_rep : str or None, default None | Representation that is inserted for all missing values: | | - If `na_rep` is None, and `others` is None, missing values in the | Series/Index are omitted from the result. | - If `na_rep` is None, and `others` is not None, a row containing a | missing value in any of the columns (before concatenation) will | have a missing value in the result. | join : {'left', 'right', 'outer', 'inner'}, default 'left' | Determines the join-style between the calling Series/Index and any | Series/Index/DataFrame in `others` (objects without an index need | to match the length of the calling Series/Index). To disable | alignment, use `.values` on any Series/Index/DataFrame in `others`. | | .. versionadded:: 0.23.0 | .. versionchanged:: 1.0.0 | Changed default of `join` from None to `'left'`. | | Returns | ------- | str, Series or Index | If `others` is None, `str` is returned, otherwise a `Series/Index` | (same type as caller) of objects is returned. | | See Also | -------- | split : Split each string in the Series/Index. | join : Join lists contained as elements in the Series/Index. | | Examples | -------- | Whe