NumPy
keyboard_arrow_down 319 guides
chevron_leftDocumentation
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 hstackChar32 topics
check_circle
Mark as learned thumb_up
0
thumb_down
0
chat_bubble_outline
0
Comment auto_stories Bi-column layout
settings
NumPy | roll method
schedule Aug 11, 2023
Last updated local_offer
Tags Python●NumPy
tocTable of Contents
expand_more Master the mathematics behind data science with 100+ top-tier guides
Start your free 7-days trial now!
Start your free 7-days trial now!
Numpy's roll(~) method shifts an array along the specified axis.
Parameters
1. a | array_like
✜ The array to perform the method on.
2. shiftlink | integer or tuple of integers
✜ The desired number of shifts.
3. axislink | number | optional
✜ The axis along which to shift the input array.
Return value
A Numpy array with elements shifted by the specified amount.
Examples
Rolling a flat array
To shift a flat array by 1, use the following:
np.roll([1,2,3,4], 1)
array([4, 1, 2, 3])
Notice how the final value of the array (i.e. 4 in this case), got placed in the very front.
Rolling a 2D array
By value
To shift a 2D array by 1, use the following:
np.roll([[1,2], [3,4]], 1)
array([[4, 1], [2, 3]])
Essentially, what we are doing is as follows:
$$\begin{pmatrix}
1&2\\
3&4\\
\end{pmatrix}\;
\to \;
\begin{pmatrix}
4&1\\
2&3\\
\end{pmatrix}$$
By row
To shift a 2D array by 1 row-wise, add the axis=0 parameter:
np.roll([[1,2], [3,4], [5,6]], 1, axis=0)
array([[5, 6], [1, 2], [3, 4]])
Essentially, we're doing the following:
$$\begin{pmatrix}
1&2\\
3&4\\
5&6\\
\end{pmatrix}\;
\to \;
\begin{pmatrix}
5&6\\
1&2\\
3&4\\
\end{pmatrix}$$
By column
To shift a 2D array by 1 column-wise, add the axis=1 parameter:
np.roll([[1,2,3], [4,5,6]], 1, axis=1)
array([[3, 1, 2], [6, 4, 5]])
Essentially, we're doing the following:
$$\begin{pmatrix}
1&2&3\\
4&5&6\\
\end{pmatrix}\;
\to \;
\begin{pmatrix}
3&1&2\\
6&4&5\\
\end{pmatrix}$$
Published by Isshin Inada
Edited by 0 others
Did you find this page useful?
thumb_up
thumb_down
Comment
Citation
Ask a question or leave a feedback...
thumb_up
0
thumb_down
0
chat_bubble_outline
0
settings
Enjoy our search
Hit / to insta-search docs and recipes!
