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Pandas Index对象

2017-05-24 13:20 204 查看

Index对象是通过有序的，可切片的集合实现的。

Index

属性（Attributes）


Function	Describe
Index.values	返回索引的值
Index.is_monotonic_increasing	是否是单调升的
Index.is_monotonic_decreasing	是否是单调减的
Index.is_unique	是否是唯一的
Index.has_duplicates
Index.dtype	索引类型
Index.inferred_type
Index.is_all_dates
Index.shape	索引的形状
Index.nbytes	返回字节数
Index.ndim	返回维度
Index.size	返回元素的个数
Index.strides	return the strides of the underlying data
Index.itemsize	return the size of the dtype of the item of the underlying data
Index.base	return the base object if the memory of the underlying data is
Index.T	return the transpose, which is by definition self
Index.memory_usage([deep])	Memory usage of my values

修改和计算（Modifying and Computations）


Function	Describe
Index.all(args,?*kwargs)	Return whether all elements are True
Index.any(args,?*kwargs)	Return whether any element is True
Index.argmin([axis])	return a ndarray of the minimum argument indexer
Index.argmax([axis])	return a ndarray of the maximum argument indexer
Index.copy([name,?deep,?dtype])	复制
Index.delete(loc)	Make new Index with passed location(-s) deleted
Index.drop(labels[,?errors])	Make new Index with passed list of labels deleted
Index.drop_duplicates(args,?*kwargs)	Return Index with duplicate values removed
Index.duplicated(args,?*kwargs)	Return boolean np.ndarray denoting duplicate values
Index.equals(other)	是否含有相同的元素
Index.factorize([sort,?na_sentinel])	Encode the object as an enumerated type or categorical variable
Index.identical(other)	Similar to equals, but check that other comparable attributes are
Index.insert(loc,?item)	Make new Index inserting new item at location.
Index.min()	最小值
Index.max()	最大值
Index.reindex(target[,?method,?level,?…])	Create index with target’s values (move/add/delete values 4000 as necessary)
Index.repeat(n,?args,?*kwargs)	Repeat elements of an Index.
Index.where(cond[,?other])	条件选取
Index.take(indices[, axis, allow_fill, …])	return a new %(klass)s of the values selected by the indices
Index.putmask(mask, value)	return a new Index of the values set with the mask
Index.set_names(names[, level, inplace])	Set new names on index.
Index.unique()	返回唯一值
Index.nunique([dropna])	Return number of unique elements in the object.
Index.value_counts([normalize, sort, …])	返回唯一值计数
Index.fillna([value, downcast])	填充缺省值
Index.dropna([how])	Return Index without NA/NaN values

转换（Conversion）


Function	Describe
Index.astype(dtype[,?copy])	Create an Index with values cast to dtypes.
Index.tolist()	转变为list
Index.to_series(**kwargs)	Create a Series with both index and values equal to the index keys

排序（Sorting）


Function	Describe
Index.argsort(args, *kwargs)	Returns the indices that would sort the index and its underlying data.
Index.sort_values([return_indexer, ascending])	Return sorted copy of Index

时间处理（Time-specific operations）


Function	Describe
Index.shift([periods,?freq])	Shift Index containing datetime objects by input number of periods and

联表（Combining / joining / set operations）


Function	Describe
Index.append(other)	Append a collection of Index options together
Index.join(other[, how, level, return_indexers])	this is an internal non-public method
Index.intersection(other)	Form the intersection of two Index objects.
Index.union(other)	Form the union of two Index objects and sorts if possible.
Index.difference(other)	Return a new Index with elements from the index that are not in other.
Index.symmetric_difference(other[, result_name])	Compute the symmetric difference of two Index objects.

选取（Selecting）


Function	Describe
Index.get_indexer(target[, method, limit, …])	Compute indexer and mask for new index given the current index.
Index.get_indexer_non_unique(target)	return an indexer suitable for taking from a non unique index
Index.get_level_values(level)	Return vector of label values for requested level, equal to the length
Index.get_loc(key[, method, tolerance])	Get integer location for requested label
Index.get_value(series, key)	Fast lookup of value from 1-dimensional ndarray.
Index.isin(values[, level])	Compute boolean array of whether each index value is found in the passed set of values.
Index.slice_indexer([start, end, step, kind])	For an ordered Index, compute the slice indexer for input labels and
Index.slice_locs([start, end, step, kind])	Compute slice locations for input labels.

分类索引CategoricalIndex


Function	Describe
CategoricalIndex	Immutable Index implementing an ordered, sliceable set.
CategoricalIndex.codes
CategoricalIndex.categories
CategoricalIndex.ordered
CategoricalIndex.rename_categories(*args, …)	Renames categories.
CategoricalIndex.reorder_categories(*args, …)	Reorders categories as specified in new_categories.
CategoricalIndex.add_categories(args, *kwargs)	Add new categories.
CategoricalIndex.remove_categories(*args, …)	Removes the specified categories.
CategoricalIndex.remove_unused_categories(…)	Removes categories which are not used.
CategoricalIndex.set_categories(args, *kwargs)	Sets the categories to the specified new_categories.
CategoricalIndex.as_ordered(args, *kwargs)	Sets the Categorical to be ordered
CategoricalIndex.as_unordered(args, *kwargs)	Sets the Categorical to be unordered

复合索引


Function	Describe
MultiIndex.from_arrays(arrays[, sortorder, …])	Convert arrays to MultiIndex
MultiIndex.from_tuples(tuples[, sortorder, …])	Convert list of tuples to MultiIndex
MultiIndex.from_product(iterables[, …])	Make a MultiIndex from the cartesian product of multiple iterables
MultiIndex.set_levels(levels[, level, …])	Set new levels on MultiIndex.
MultiIndex.set_labels(labels[, level, …])	Set new labels on MultiIndex.
MultiIndex.to_hierarchical(n_repeat[, n_shuffle])	Return a MultiIndex reshaped to conform to the shapes given by n_repeat and n_shuffle.
MultiIndex.is_lexsorted()	Return True if the labels are lexicographically sorted
MultiIndex.droplevel([level])	Return Index with requested level removed.
MultiIndex.swaplevel([i, j])	Swap level i with level j.
MultiIndex.reorder_levels(order)	Rearrange levels using input order.

时间索引DatetimeIndex

属性

参考Series里面的Datetime类型的介绍

时间索引可以用字符串

“2011/01/01” 搜索某一天

“2011/01”搜索某一月，当月所有数据都会输出


Function	Describe
DatetimeIndex.year	The year of the datetime
DatetimeIndex.month	The month as January=1, December=12
DatetimeIndex.day	The days of the datetime
DatetimeIndex.hour	The hours of the datetime
DatetimeIndex.minute	The minutes of the datetime
DatetimeIndex.second	The seconds of the datetime
DatetimeIndex.microsecond	The microseconds of the datetime
DatetimeIndex.nanosecond	The nanoseconds of the datetime
DatetimeIndex.date	Returns numpy array of python datetime.date objects (namely, the date part of Timestamps without timezone information).
DatetimeIndex.time	Returns numpy array of datetime.time.
DatetimeIndex.dayofyear	The ordinal day of the year
DatetimeIndex.weekofyear	The week ordinal of the year
DatetimeIndex.week	The week ordinal of the year
DatetimeIndex.dayofweek	The day of the week with Monday=0, Sunday=6
DatetimeIndex.weekday	The day of the week with Monday=0, Sunday=6
DatetimeIndex.weekday_name	The name of day in a week (ex: Friday)
DatetimeIndex.quarter	The quarter of the date
DatetimeIndex.tz
DatetimeIndex.freq	get/set the frequncy of the Index
DatetimeIndex.freqstr	Return the frequency object as a string if its set, otherwise None
DatetimeIndex.is_month_start	Logical indicating if first day of month (defined by frequency)
DatetimeIndex.is_month_end	Logical indicating if last day of month (defined by frequency)
DatetimeIndex.is_quarter_start	Logical indicating if first day of quarter (defined by frequency)
DatetimeIndex.is_quarter_end	Logical indicating if last day of quarter (defined by frequency)
DatetimeIndex.is_year_start	Logical indicating if first day of year (defined by frequency)
DatetimeIndex.is_year_end	Logical indicating if last day of year (defined by frequency)
DatetimeIndex.is_leap_year	Logical indicating if the date belongs to a leap year
DatetimeIndex.inferred_freq

选取Selecting


Function	Describe
DatetimeIndex.indexer_at_time(time[, asof])	Select values at particular time of day (e.g.
DatetimeIndex.indexer_between_time(…[, …])	Select values between particular times of day (e.g., 9:00-9:30AM).

特定的时间方法


Function	Describe
DatetimeIndex.normalize()	Return DatetimeIndex with times to midnight.
DatetimeIndex.strftime(date_format)	Return an array of formatted strings specified by date_format, which supports the same string format as the python standard library.
DatetimeIndex.snap([freq])	Snap time stamps to nearest occurring frequency
DatetimeIndex.tz_convert(tz)	Convert tz-aware DatetimeIndex from one time zone to another (using
DatetimeIndex.tz_localize(args, *kwargs)	Localize tz-naive DatetimeIndex to given time zone (using
DatetimeIndex.round(freq, args, *kwargs)	round the index to the specified freq
DatetimeIndex.floor(freq)	floor the index to the specified freq
DatetimeIndex.ceil(freq)	ceil the index to the specified freq

转化Conversion


Function	Describe
DatetimeIndex.to_datetime([dayfirst])
DatetimeIndex.to_period([freq])	Cast to PeriodIndex at a particular frequency
DatetimeIndex.to_perioddelta(freq)	Calcuates TimedeltaIndex of difference between index values and index converted to PeriodIndex at specified freq.
DatetimeIndex.to_pydatetime()	Return DatetimeIndex as object ndarray of datetime.datetime objects
DatetimeIndex.to_series([keep_tz])	Create a Series with both index and values equal to the index keys

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