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Method argpartition
NumPy Random Generator4 topics
Method choiceMethod dotMethod finfoMethod histogramMethod iinfoMethod maxMethod meanMethod placeMethod rootsMethod seedMethod uniformMethod viewMethod zerosMethod sumObject busdaycalendarMethod is_busdayProperty dtypeMethod uniqueMethod loadtxtMethod vsplitMethod fliplrMethod setdiff1dMethod msortMethod argsortMethod lexsortMethod aroundMethod nanmaxMethod nanminMethod nanargmaxMethod nanargminMethod argmaxMethod argminProperty itemsizeMethod spacingMethod fixMethod ceilMethod diffProperty flatProperty realProperty baseMethod flipMethod deleteMethod amaxMethod aminMethod logical_xorMethod logical_orMethod logical_notMethod logical_andMethod logaddexpMethod logaddexp2Method logspaceMethod not_equalMethod equalMethod greater_equalMethod lessMethod less_equalMethod remainderMethod modMethod emptyMethod greaterMethod isfiniteMethod busday_countMethod repeatMethod varMethod random_sampleMethod randomMethod signMethod stdMethod absoluteMethod absMethod sortMethod randintMethod isrealMethod linspaceMethod gradientMethod allMethod sampleProperty TProperty imagMethod covMethod insertMethod logMethod log1pMethod exp2Method expm1Method expMethod arccosMethod cosMethod arcsinMethod sinMethod tanMethod fromiterMethod trim_zerosMethod diagflatMethod savetxtMethod count_nonzeroProperty sizeProperty shapeMethod reshapeMethod resizeMethod triuMethod trilMethod eyeMethod arangeMethod fill_diagonalMethod tileMethod saveMethod transposeMethod swapaxesMethod meshgridProperty mgridMethod rot90Method log2Method radiansMethod deg2radMethod rad2degMethod degreesMethod log10Method appendMethod cumprodProperty nbytesMethod tostringProperty dataMethod modfMethod fmodMethod tolistMethod datetime_as_stringMethod datetime_dataMethod array_splitMethod itemsetMethod floorMethod put_along_axisMethod cumsumMethod bincountMethod putMethod putmaskMethod takeMethod hypotMethod sqrtMethod squareMethod floor_divideMethod triMethod signbitMethod flattenMethod ravelMethod rollMethod isrealobjMethod diagMethod diagonalMethod quantileMethod onesMethod iscomplexobjMethod iscomplexMethod isscalarMethod divmodMethod isnatMethod percentileMethod isnanMethod divideMethod addMethod reciprocalMethod positiveMethod subtractMethod medianMethod isneginfMethod isposinfMethod float_powerMethod powerMethod negativeMethod maximumMethod averageMethod isinfMethod multiplyMethod busday_offsetMethod identityMethod interpMethod squeezeMethod get_printoptionsMethod savez_compressedMethod savezMethod loadMethod asfarrayMethod clipMethod arrayMethod array_equivMethod array_equalMethod frombufferMethod set_string_functionMethod matmulMethod genfromtxtMethod fromfunctionMethod asscalarMethod searchsortedMethod full_likeMethod fullMethod shares_memoryMethod ptpMethod digitizeMethod argwhereMethod geomspaceMethod zeros_likeMethod fabsMethod flatnonzeroMethod vstackMethod dstackMethod fromstringMethod tobytesMethod expand_dimsMethod ranfMethod arctanMethod itemMethod extractMethod compressMethod chooseMethod asarrayMethod asmatrixMethod allcloseMethod iscloseMethod anyMethod corrcoefMethod truncMethod prodMethod crossMethod true_divideMethod hsplitMethod splitMethod rintMethod ediff1dMethod lcmMethod gcdMethod cbrtMethod flipudProperty ndimMethod array2stringMethod set_printoptionsMethod whereMethod hstack
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chevron_left Documentation
Method argpartition
NumPy Random Generator4 topics
Method choiceMethod dotMethod finfoMethod histogramMethod iinfoMethod maxMethod meanMethod placeMethod rootsMethod seedMethod uniformMethod viewMethod zerosMethod sumObject busdaycalendarMethod is_busdayProperty dtypeMethod uniqueMethod loadtxtMethod vsplitMethod fliplrMethod setdiff1dMethod msortMethod argsortMethod lexsortMethod aroundMethod nanmaxMethod nanminMethod nanargmaxMethod nanargminMethod argmaxMethod argminProperty itemsizeMethod spacingMethod fixMethod ceilMethod diffProperty flatProperty realProperty baseMethod flipMethod deleteMethod amaxMethod aminMethod logical_xorMethod logical_orMethod logical_notMethod logical_andMethod logaddexpMethod logaddexp2Method logspaceMethod not_equalMethod equalMethod greater_equalMethod lessMethod less_equalMethod remainderMethod modMethod emptyMethod greaterMethod isfiniteMethod busday_countMethod repeatMethod varMethod random_sampleMethod randomMethod signMethod stdMethod absoluteMethod absMethod sortMethod randintMethod isrealMethod linspaceMethod gradientMethod allMethod sampleProperty TProperty imagMethod covMethod insertMethod logMethod log1pMethod exp2Method expm1Method expMethod arccosMethod cosMethod arcsinMethod sinMethod tanMethod fromiterMethod trim_zerosMethod diagflatMethod savetxtMethod count_nonzeroProperty sizeProperty shapeMethod reshapeMethod resizeMethod triuMethod trilMethod eyeMethod arangeMethod fill_diagonalMethod tileMethod saveMethod transposeMethod swapaxesMethod meshgridProperty mgridMethod rot90Method log2Method radiansMethod deg2radMethod rad2degMethod degreesMethod log10Method appendMethod cumprodProperty nbytesMethod tostringProperty dataMethod modfMethod fmodMethod tolistMethod datetime_as_stringMethod datetime_dataMethod array_splitMethod itemsetMethod floorMethod put_along_axisMethod cumsumMethod bincountMethod putMethod putmaskMethod takeMethod hypotMethod sqrtMethod squareMethod floor_divideMethod triMethod signbitMethod flattenMethod ravelMethod rollMethod isrealobjMethod diagMethod diagonalMethod quantileMethod onesMethod iscomplexobjMethod iscomplexMethod isscalarMethod divmodMethod isnatMethod percentileMethod isnanMethod divideMethod addMethod reciprocalMethod positiveMethod subtractMethod medianMethod isneginfMethod isposinfMethod float_powerMethod powerMethod negativeMethod maximumMethod averageMethod isinfMethod multiplyMethod busday_offsetMethod identityMethod interpMethod squeezeMethod get_printoptionsMethod savez_compressedMethod savezMethod loadMethod asfarrayMethod clipMethod arrayMethod array_equivMethod array_equalMethod frombufferMethod set_string_functionMethod matmulMethod genfromtxtMethod fromfunctionMethod asscalarMethod searchsortedMethod full_likeMethod fullMethod shares_memoryMethod ptpMethod digitizeMethod argwhereMethod geomspaceMethod zeros_likeMethod fabsMethod flatnonzeroMethod vstackMethod dstackMethod fromstringMethod tobytesMethod expand_dimsMethod ranfMethod arctanMethod itemMethod extractMethod compressMethod chooseMethod asarrayMethod asmatrixMethod allcloseMethod iscloseMethod anyMethod corrcoefMethod truncMethod prodMethod crossMethod true_divideMethod hsplitMethod splitMethod rintMethod ediff1dMethod lcmMethod gcdMethod cbrtMethod flipudProperty ndimMethod array2stringMethod set_printoptionsMethod whereMethod hstack
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NumPy | sort method

NumPy
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schedule Jul 1, 2022
Last updated
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Numpy's sort(~) method returns the sorted copy of the input array. Note that the original array is left intact.

Parameters

1. a | array_like

The input array.

2. axislink | int | optional

The axis along which to sort the input array. For 2D arrays, the allowed values are as follows:

Value

Meaning

None

Flattens the array and sorts it

0

Sorts column-wise

1

Sorts row-wise

By default, axis=-1 which means that sorting is performed only on the last axis. For 2D arrays, this means that the default sorting behaviour is row-wise.

3. kind | string | optional

The sorting algorithm to use. Currently, Numpy offers the following choices:

Kind

Speed

Worst case

Memory

Stable

quicksort

1 (fast)

O(n^2)

0

no

mergesort

2

O(nlogn)

~n/2

yes

timsort

2

O(nlogn)

~n/2

yes

heapsort

3 (slow)

O(nlogn)

0

no

Sorting algorithms that are "stable" retain the relative ordering of duplicate values. For instance, suppose you are sorting the array [(2,3), (2,1), (4,5)] by the first element of each tuple. We have a duplicate value of 2 here, so stable sorting algorithms ensure that (2,3) will always come before (2,1) since that is how they are ordered originally. Unstable searches provide no guarantee that such ordering is retained.

By default, kind="quicksort".

WARNING

The datatype determines whether mergesort or timsort is used

Despite the fact that you can specify either mergesort or timsort, Numpy will ultimately make its decision on the data-type of the array. There is currently no way of enforcing your choice of algorithm between the two.

NOTE

Timsort offers the best performance for sorted or nearly sorted arrays

Timsort is the latest searching algorithm added to Numpy (version 1.17). Timsort is still nearly as efficient as mergesort for randomly arranged numbers.

4. orderlink | string or list of strings | optional

The field to sort by. This is only applicable to structured arrays - see our example below for clarification.

Return value

A Numpy array that is a sorted copy of the input array.

Examples

Sorting one-dimensional arrays

x = np.array([1,4,2,3])
np.sort(x)
array([1, 2, 3, 4])

Sorting two-dimensional arrays

Suppose we have the following 2D array:

x = np.array([[1,4],[3,2]])
x
array([[1, 4],
[3, 2]])

Sorting the flattened array

np.sort(x, axis=None)
array([1, 2, 3, 4])

Sorting row-wise

np.sort(x) # or explicitly set axis=1
array([[1, 4],
[2, 3]])

Sorting column-wise

np.sort(x, axis=0)
array([[1, 2],
[3, 4]])

Specifying order for structured arrays

Suppose we have the following structured array:

dtype = [('name', 'S15'), ('age', int)]
values = [('Bob', 35), ('Alex', 15),('Cathy', 24)]
x = np.array(values, dtype)
x
array([(b'Bob', 35), (b'Alex', 15), (b'Cathy', 24)],
dtype=[('name', 'S15'), ('age', '<i8')])

Our array x consists of three tuples, with the 1st element as the name, and the 2nd element as the age.

To sort by name:

np.sort(x, order="name")
array([(b'Alex', 15), (b'Bob', 35), (b'Cathy', 24)],
dtype=[('name', 'S15'), ('age', '<i8')])

Notice how the tuples are sorted by name: Alex, Bob and then Cathy.

To sort by age:

np.sort(x, order="age")
array([(b'Bob', 15), (b'Cathy', 24), (b'Alex', 35)],
dtype=[('name', 'S15'), ('age', '<i8')])

Notice how tuples are sorted by age: 15, 24 and then 35.

You could also pass in an array of labels to sort by (e.g. order=["name", "age"]), which would sort the array by name first, and then by age.

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