what is the difference bet w een a n u mp y arra y and a
play

What is the difference bet w een a N u mP y arra y and a list ? P R - PowerPoint PPT Presentation

Apr 07, 2024 •240 likes •1.17k views

What is the difference bet w een a N u mP y arra y and a list ? P R AC TIC IN G C OD IN G IN TE R VIE W QU E STION S IN P YTH ON Kirill Smirno v Data Science Cons u ltant , Altran N u mP y arra y import numpy as np num_array = np.array([1, 2,

  1. What is the difference bet w een a N u mP y arra y and a list ? P R AC TIC IN G C OD IN G IN TE R VIE W QU E STION S IN P YTH ON Kirill Smirno v Data Science Cons u ltant , Altran

  2. N u mP y arra y import numpy as np num_array = np.array([1, 2, 3, 4, 5]) print(num_array) [1 2 3 4 5] num_list = [1, 2, 3, 4, 5] print(num_list) [1, 2, 3, 4, 5] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  3. Similarities bet w een an arra y and a list num_array = np.array([1, 2, 3, 4, 5]) num_list = [1, 2, 3, 4, 5] for item in num_array: for item in num_list: print(item) print(item) 1 1 2 2 3 3 4 4 5 5 PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  4. Similarities bet w een an arra y and a list num_array = np.array([1, 2, 3, 4, 5]) num_list = [1, 2, 3, 4, 5] num_array[1] num_list[1] 2 2 num_array[1:4] num_list[1:4] array([2, 3, 4]) [2, 3, 4] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  5. Similarities bet w een an arra y and a list num_array = np.array([1, 2, 3, 4, 5]) num_list = [1, 2, 3, 4, 5] num_array[3] = 40 num_list[3] = 40 print(num_array) print(num_list) [1 2 3 40 5] [1, 2, 3, 40, 5] num_array[0:3] = [10, 20, 30] num_list[0:3] = [10, 20, 30] print(num_array) print(num_list) [10 20 30 40 5] [10, 20, 30, 40, 5] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  6. Difference bet w een an arra y an a list N u mP y arra y s are designed for high e � cienc y comp u tations N u mP y arra y s store v al u es of the same t y pe PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  7. . dt y pe propert y num_array = np.array([1, 2, 3, 4, 5]) num_array.dtype dtype('int64') PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  8. Changing the data t y pe of an element num_array = np.array([1, 2, 3, 4, 5]) num_list = [1, 2, 3, 4, 5] num_list[2] = 'three' num_array[2] = 'three' print(num_list) ValueError [1, 2, 'three', 4, 5] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  9. Specif y ing the data t y pe e x plicitl y num_array = np.array([1, 2, 3, 4, 5]) num_array = np.array([1, 2, 3, 4, 5], dtype = np.dtype('int64')) print(num_array) [1 2 3 4 5] num_array.dtype dtype('int64') PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  10. Specif y ing the data t y pe e x plicitl y num_array = np.array([1, 2, 3, 4, 5]) num_array = np.array([1, 2, 3, 4, 5], dtype = np.dtype('str')) print(num_array) ['1' '2' '3' '4' '5'] num_array.dtype dtype('<U1') PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  11. Object as a data t y pe num_array = np.array([1, 2, 3, 4, 5], dtype = np.dtype('O')) num_array[2] = 'three' print(num_array) [1 2 'three' 4 5] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  12. Difference bet w een an arra y and a list N u mP y arra y s are designed for high e � cienc y comp u tations N u mP y arra y s store v al u es of a concrete data t y pe N u mP y arra y s ha v e a special w a y to access its elements PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  13. Accessing items list2d = [ array2d = np.array([ [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15] [11, 12, 13, 14, 15] ] ]) # Retrieve 8 # Retrieve 8 list2d[1][2] array2d[1][2] 8 8 PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  14. Accessing items list2d = [ array2d = np.array([ [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15] [11, 12, 13, 14, 15] ] ]) # Retrieve 8 # Retrieve 8 list2d[1][2] array2d[1, 2] 8 8 PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  15. Accessing items list2d = [ array2d = np.array([ [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15] [11, 12, 13, 14, 15] ] ]) # Retrieve [[2, 3, 4], [7, 8, 9]] # Retrieve [[2, 3, 4], [7, 8, 9]] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  16. Accessing items list2d = [ array2d = np.array([ [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15] [11, 12, 13, 14, 15] ] ]) # Retrieve [[2, 3, 4], [7, 8, 9]] # Retrieve [[2, 3, 4], [7, 8, 9]] [ [list2d[j][1:4] for j in range(0, 2)] ] [[2, 3, 4], [7, 8, 9]] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  17. Accessing items list2d = [ array2d = np.array([ [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15] [11, 12, 13, 14, 15] ] ]) # Retrieve [[2, 3, 4], [7, 8, 9]] # Retrieve [[2, 3, 4], [7, 8, 9]] [ array2d[0:2, 1:4] [list2d[j][1:4] for j in range(0, 2)] ] array([[2, 3, 4], [7, 8, 9]]) [[2, 3, 4], [7, 8, 9]] PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  18. Difference bet w een an arra y and a list N u mP y arra y s are designed for high e � cienc y comp u tations N u mP y arra y s store v al u es of a concrete data t y pe N u mP y arra y s ha v e a special w a y to access its elements N u mP y arra y s ha v e e � cient w a y to perform operations on them . PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  19. Operations +, -, *, / w ith lists num_list1 = [1, 2, 3] num_list1 * num_list2 num_list2 = [10, 20, 30] TypError num_list1 + num_list2 num_list2 / num_list1 [1, 2, 3, 10, 20, 30] TypeError num_list2 - num_list1 TypeError PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  20. Operations +, -, *, / w ith arra y s num_array1 = np.array([1, 2, 3]) num_array1 * num_array2 num_array2 = np.array([10, 20, 30]) array([10, 40, 90]) num_array1 + num_array2 num_array2 / num_array1 array([11, 22, 33]) array([10, 10, 10]) num_array2 - num_array1 array([9, 18, 27]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  21. Operations +, -, *, / w ith m u ltidimensional arra y s num_array1 = np.array([ num_array1 + num_array2 [1, 2, 3, 4, 5], [6, 7, 8, 9, 10], array([[ 11, 22, 33, 44, 55], [11, 12, 13,14, 15] [ 66, 77, 88, 99, 110], ]) [121, 132, 143, 154, 165]]) num_array2 = np.array([ [10, 20, 30, 40, 50], num_array2 / num_array1 [60, 70, 80, 90, 100], [110, 120, 130,140, 150] array([[10., 10., 10., 10., 10.], ]) [10., 10., 10., 10., 10.], [10., 10., 10., 10., 10.]]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  22. Conditional operations > , < , >= , <= , == , != num_array = np.array([-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5]) num_array < 0 array([True, True, True, False, False, False, False]) num_array[num_array < 0] array([-5, -4, -3, -2, -1]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  23. Broadcasting num_array = np.array([1, 2, 3]) num_list = [1, 2, 3] num_array * 3 num_list * 3 array([3, 6, 9]) [1, 2, 3, 1, 2, 3, 1, 2, 3] num_array + 3 array([4, 5, 6]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  24. Broadcasting w ith m u ltidimensional arra y s array2d 3 x 4 ( ) array2d / array1d array2d = np.array([ array([[1., 1., 1., 1.], [1, 2, 3, 4], [1., 1., 1., 1.], [1, 2, 3, 4], [1., 1., 1., 1.]]) [1, 2, 3, 4] ]) array1d 1 x 4 ( ) array1d = np.array([1, 2, 3, 4]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  25. Broadcasting w ith m u ltidimensional arra y s array2d 3 x 4 ( ) array2d / array1d array2d = np.array([ array([[1. , 2. , 3. , 4. ], [1, 2, 3, 4], [0.5 , 1. , 1.5 , 2. ], [1, 2, 3, 4], [0.333, 0.667, 1. , 1.333]]) [1, 2, 3, 4] ]) array1d 3 x 1 ( ) array1d = np.array([[1], [2], [3]]) PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  26. Let ' s practice P R AC TIC IN G C OD IN G IN TE R VIE W QU E STION S IN P YTH ON

  27. Ho w to u se the . appl y() method on a DataFrame ? P R AC TIC IN G C OD IN G IN TE R VIE W QU E STION S IN P YTH ON Kirill Smirno v Data Science Cons u ltant , Altran

  28. Dataset import pandas as pd scores = pd.read_csv('exams.csv') scores = scores[['math score', 'reading score', 'writing score']] print(scores.head()) math score reading score writing score 0 74 86 82 1 44 49 53 2 54 46 43 3 88 95 92 4 85 81 81 PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  29. Defa u lt . appl y() df.apply(function) import numpy as np scores_new = scores.apply(np.sqrt) print(scores.head()) print(score_new) math score reading score writing score math score reading score writing score 0 74 86 82 0 8.602325 9.273618 9.055385 1 44 49 53 1 6.633250 7.000000 7.280110 2 54 46 43 2 7.348469 6.782330 6.557439 3 88 95 92 3 9.380832 9.746794 9.591663 4 85 81 81 4 9.219544 9.000000 9.000000 ... PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

  30. Defa u lt . appl y() df.apply(function) import numpy as np scores_new = scores.apply(np.mean) print(scores.head()) print(score_new.head()) math score reading score writing score math score 65.18 0 74 86 82 reading score 69.28 1 44 49 53 writing score 67.96 2 54 46 43 dtype: float64 3 88 95 92 4 85 81 81 type(scores_new) pandas.core.series.Series PRACTICING CODING INTERVIEW QUESTIONS IN PYTHON

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend

American R Recovery and d Reinvestment Act of Reinvestment Act of 2009 ARRA ARRA

American R Recovery and d Reinvestment Act of Reinvestment Act of 2009 ARRA ARRA

American R Recovery and d Reinvestment Act of Reinvestment Act of 2009 ARRA ARRA Preliminary Staff Level Discussion 2/26/2009 Document 1 ARRA Participants in the Webinar today will include a variety of Illinois Environmental

569 views • 30 slides
Reinvestment Act of 2009 (ARRA) 1 ARRA Temporarily Creates a Distinct Program Within the

Reinvestment Act of 2009 (ARRA) 1 ARRA Temporarily Creates a Distinct Program Within the

California Department of Public Health Safe Drinking Water State Revolving Fund The American Recovery and Reinvestment Act of 2009 (ARRA) 1 ARRA Temporarily Creates a Distinct Program Within the Base SRF Program BASE SRF PROGRAM ARRA

358 views • 16 slides
American Recovery and Reinvestment Act (ARRA) Quarterly Expenditure Reporting ARRA State Agency

American Recovery and Reinvestment Act (ARRA) Quarterly Expenditure Reporting ARRA State Agency

American Recovery and Reinvestment Act (ARRA) Quarterly Expenditure Reporting ARRA State Agency and Higher Education Workgroup December 17, 2009 LEGISLATIVE BUDGET BOARD Topics Reporting Requirements ARRA Quarterly Expenditure

516 views • 16 slides
ARRA Incentive Funds Approval to Combine ARRA Balances into Regular Incentive Funds No

ARRA Incentive Funds Approval to Combine ARRA Balances into Regular Incentive Funds No

6/6/2018 Financial Quality Assurance Department Title IV-D Issues Clerk's Summer Conference June 14, 2018 Indianapolis, IN Presented by: John Mallers, CPA ARRA Incentive Funds Approval to Combine ARRA Balances into Regular Incentive

194 views • 8 slides
Working w ith 2 D arra y s IN TR OD U C TION TO DATA VISU AL IZATION IN P YTH ON Br y an Van de

Working w ith 2 D arra y s IN TR OD U C TION TO DATA VISU AL IZATION IN P YTH ON Br y an Van de

Working w ith 2 D arra y s IN TR OD U C TION TO DATA VISU AL IZATION IN P YTH ON Br y an Van de Ven Core De v eloper of Bokeh Reminder : N u mP y arra y s Homogeneo u s in t y pe Calc u lations all at once Inde x ing w ith brackets : A[index]

671 views • 41 slides
Causal inference Part II: Difference In Difference and Instrumental Variables Difference in

Causal inference Part II: Difference In Difference and Instrumental Variables Difference in

Causal inference Part II: Difference In Difference and Instrumental Variables Difference in difference Card &amp; Krueger (1995,AER) Rise in minimum wage from 4,2$ to 5,05$ in April 1992 in the State of New Jersey. Research question:

405 views • 28 slides
Ch u nking Arra y s in Dask PAR AL L E L P R OG R AMMIN G W ITH DASK IN P YTH ON Dha v ide

Ch u nking Arra y s in Dask PAR AL L E L P R OG R AMMIN G W ITH DASK IN P YTH ON Dha v ide

Ch u nking Arra y s in Dask PAR AL L E L P R OG R AMMIN G W ITH DASK IN P YTH ON Dha v ide Ar u liah Director of Training , Anaconda What w e 'v e seen so far ... Meas u ring memor y u sage Reading large les in ch u nks Comp u ting w ith

455 views • 41 slides
Understanding ARRA EHR Incentives and Meaningful Use (Getting the $$) Linda Parks Physician's

Understanding ARRA EHR Incentives and Meaningful Use (Getting the $$) Linda Parks Physician's

Understanding ARRA EHR Incentives and Meaningful Use (Getting the $$) Linda Parks Physician's Computer Company PCC Users' Conference July, 2013 What Money? As part of the American Recovery and Reinvestment Act, the government established a

420 views • 11 slides
Taking OpenEMR, a GPL EMR to ARRA Meaningful Use Certification and Beyond Reference sites:

Taking OpenEMR, a GPL EMR to ARRA Meaningful Use Certification and Beyond Reference sites:

Taking OpenEMR, a GPL EMR to ARRA Meaningful Use Certification and Beyond Reference sites: www.oemr.org - our official web home page openmedsoftare.org - our project wiki, access to online demo and all lots more

190 views • 7 slides
L a rg e Ante nna Arra y Re moting using RoF T e c hnique s for Ra dioa stronomic a l

L a rg e Ante nna Arra y Re moting using RoF T e c hnique s for Ra dioa stronomic a l

L a rg e Ante nna Arra y Re moting using RoF T e c hnique s for Ra dioa stronomic a l Applic ation E mb ra c e Me e ting , Bo lo g na 23 Se pte mb e r 2005 Outline T he BE ST Pro je c t fo r the No rthe rn Cro ss Ro FT e c

398 views • 35 slides
Follow-up Questions from JBC Hearing Department of Transportation 11/16/09 1. Please provide

Follow-up Questions from JBC Hearing Department of Transportation 11/16/09 1. Please provide

Follow-up Questions from JBC Hearing Department of Transportation 11/16/09 1. Please provide additional detail on the process for ensuring accountability for the ARRA funds, including the quality of the data feeding ARRA reports. The Department

68 views • 6 slides
American Recovery and Reinvestment Act (ARRA)- Impact of Economic Stimulus on NIH Lawrence A.

American Recovery and Reinvestment Act (ARRA)- Impact of Economic Stimulus on NIH Lawrence A.

American Recovery and Reinvestment Act (ARRA)- Impact of Economic Stimulus on NIH Lawrence A. Tabak, DDS, PhD. Acting Deputy Director National Institutes of Health NIH is grateful to President Obama and Congress for the opportunity for NIH to

471 views • 20 slides
Non Secondary Course Coding Iowa Department of Education Non-Secondary ARRA (American

Non Secondary Course Coding Iowa Department of Education Non-Secondary ARRA (American

Non Secondary Course Coding Iowa Department of Education Non-Secondary ARRA (American Recovery and Reinvestment Act) reporting requirement Need to link teachers to students in grades 3-8 Math Reading Language Arts Science

377 views • 24 slides
' $ \Similarit y Query Pro cessing using Disk Arra ys&quot; Ap ostolos N. P apadop

' $ \Similarit y Query Pro cessing using Disk Arra ys&quot; Ap ostolos N. P apadop

' $ \Similarit y Query Pro cessing using Disk Arra ys&quot; Ap ostolos N. P apadop oulos &amp; Y annis Manolop oulos Departmen t of Informatics, Aristotle Univ ersit y Thessaloniki, Greece A CM SIGMOD Conference,

562 views • 23 slides
RECOVERY ZONE BONDS The American Recovery and Reinvestment Act of 2009 (the ARRA) created

RECOVERY ZONE BONDS The American Recovery and Reinvestment Act of 2009 (the ARRA) created

RECOVERY ZONE BONDS The American Recovery and Reinvestment Act of 2009 (the ARRA) created two new categories of bonds which can be used to finance a wide range of projects, including real estate developments and public infrastructure: A.

267 views • 9 slides
DSS Director Call NC FAST Update April 8, 2015 1 FNS Issuances Over Time 1 Nov 2013 ARRA

DSS Director Call NC FAST Update April 8, 2015 1 FNS Issuances Over Time 1 Nov 2013 ARRA

North Carolina Department of Health &amp; Human Services DSS Director Call NC FAST Update April 8, 2015 1 FNS Issuances Over Time 1 Nov 2013 ARRA funding was removed by policy. 2 Oct 2014 Benefits increased based on Federal COLA adjustments.

320 views • 19 slides
t t s

t t s

t t s tr t rr strt s r s s t

373 views • 8 slides
Biometric T echnologies Dr. Issa Traore ECE Department, University of Victoria Information

Biometric T echnologies Dr. Issa Traore ECE Department, University of Victoria Information

Biometric T echnologies Dr. Issa Traore ECE Department, University of Victoria Information Security and Object T echnology (ISOT) Lab http://www.isot.ece.uvic.ca 1 Agenda Introduction Applications Requirements Biometric

268 views • 16 slides
Interaco Homem-Mquina 2- Os Humanos Pedro Campos dme.uma.pt/pcampos pcampos@uma.pt O

Interaco Homem-Mquina 2- Os Humanos Pedro Campos dme.uma.pt/pcampos pcampos@uma.pt O

Interaco Homem-Mquina 2- Os Humanos Pedro Campos dme.uma.pt/pcampos pcampos@uma.pt O Modelo Humano de Processamento Viso simplificada do processamento humano envolvido na interaco com um sistema computacional Os Humanos

432 views • 27 slides
Ocular Ocular Pointers and pitfalls in: trauma trauma Corneal injuries Globe

Ocular Ocular Pointers and pitfalls in: trauma trauma Corneal injuries Globe

2/1/2013 objectives Ocular Ocular Pointers and pitfalls in: trauma trauma Corneal injuries Globe injuries Eyelid lacerations David Duong, MD MS David Duong, MD MS University of California, San Francisco University of

603 views • 6 slides
1 Information Visualization for Medical Knowledge Discovery Ben Shneiderman ben@cs.umd.edu

1 Information Visualization for Medical Knowledge Discovery Ben Shneiderman ben@cs.umd.edu

Visualization for Electronic Health Records: Promoting Patient-Centered Cognitive Support for Physician Decision-Making 10:00am Welcome &amp; Introductions 10:20am Ben Shneiderman, Catherine Plaisant, David Wang, John Guerra, Angela Noh Univ

774 views • 45 slides
Rilpivirine-Tenofovir alafenamide-Emtricitabine ( Odefsey ) Prepared by: Brian R. Wood, MD David

Rilpivirine-Tenofovir alafenamide-Emtricitabine ( Odefsey ) Prepared by: Brian R. Wood, MD David

Rilpivirine-Tenofovir alafenamide-Emtricitabine ( Odefsey ) Prepared by: Brian R. Wood, MD David H. Spach, MD Last Updated: December 22, 2019 Rilpivirine-Tenofovir Alafenamide-Emtricitabine ( Odefsy) Odefsy [oh-DEF-see] Rilpivirine-Tenofovir

235 views • 20 slides
Na#onal Food For#fica#on Assessment Survey in Tanzania, 2015

Na#onal Food For#fica#on Assessment Survey in Tanzania, 2015

Na#onal Food For#fica#on Assessment Survey in Tanzania, 2015 Overview and methods Sylvia Meku Manager of Social and Demographics Sta9s9cs Department

1.25k views • 75 slides
The effect of diet type and nutrients on blood glucose levels using Fosr models Nihan Acar-Denizli

The effect of diet type and nutrients on blood glucose levels using Fosr models Nihan Acar-Denizli

The effect of diet type and nutrients on blood glucose levels using Fosr models Nihan Acar-Denizli 1 Pedro Delicado 2 Belchin Adriyanov Kostov 1 2 az-Rizzolo 3 Diana A. D o 4 Ramon Gomis 3 Antoni Sis 1 Mimar Sinan G uzel Sanatlar

862 views • 50 slides

More recommend