1 Objective Questions |
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2 ------------------- |
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3 |
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4 .. A mininum of 8 questions here (along with answers) |
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5 |
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6 1. Given the array, ``A = array([12, 15, 18, 21])``, how do we access |
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7 the element ``18``? |
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8 |
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9 Answer: ``A[2]`` |
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10 |
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11 #. Given the array, ``A = array([12, 15, 18, 21])``, what element is |
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12 accessed by ``A[1]`` |
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13 |
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14 Answer: ``15`` |
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15 |
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16 #. Given the array, ``A = array([12, 15, 18, 21])``, what element is |
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17 accessed by ``A[-3]``? |
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18 |
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19 Answer: ``15`` |
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20 |
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21 #. Given the array, ``A = array([12, 15, 18, 21])``, how do you change |
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22 the element ``15`` to ``51``? |
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23 |
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24 Answer: ``A[1] = 51`` |
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25 |
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26 #. Given the array, ``A = array([12, 15, 18, 21])``, what is ``A`` |
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27 after the execution of the statement ``A[3] = 24``? |
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28 |
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29 Answer: ``array([12, 15, 18, 24])`` |
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30 |
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31 #. Given the array, ``A = array([12, 15, 18, 21])``, what is the |
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32 result of the statement, ``A[4] = 24``? |
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33 |
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34 Answer: IndexError: index out of bounds |
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35 |
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36 #. Given the array, ``B = array([[12, 15], [18, 21]])``, how do we |
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37 access the element ``18``? |
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38 |
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39 Answer: ``A[0, 0]`` |
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40 |
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41 #. Given the array, ``B = array([[12, 15], [18, 21]])``, what is the |
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42 result of ``B[1]``? |
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43 |
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44 Answer: ``array([18, 21])`` |
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45 |
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46 #. Given the array, ``B = array([[12, 15], [18, 21]])``, what is the |
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47 result of ``B[1, 1]``? |
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48 |
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49 Answer: ``21`` |
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50 |
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51 #. Given the array, ``B = array([[12, 15], [18, 21]])``, what element |
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52 is accessed by ``B[-1, -2]``? |
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53 |
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54 Answer: ``18`` |
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55 |
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56 #. Given the array, ``B = array([[12, 15], [18, 21]])``, how do you |
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57 change the element ``15`` to ``51``? |
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58 |
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59 Answer: ``B[0, 1] = 51`` |
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60 |
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61 #. Given the array, ``B = array([[12, 15], [18, 21]])``, what is the |
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62 value of B, after executing, ``B[0] = 0``? |
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63 |
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64 Answer: ``array([[0, 0], [18, 21]])`` |
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65 |
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66 #. Given the array, |
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67 |
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68 :: |
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69 |
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70 B = array([[10, 11, 12, 13], |
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71 [20, 21, 22, 23], |
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72 [30, 31, 32, 33], |
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73 [40, 41, 42, 43]]) |
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74 |
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75 Obtain the elements, ``[[21, 22], [32, 32]]`` |
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76 |
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77 Answer: ``B[1:3, 1:3]`` |
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78 |
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79 #. Given the array, |
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80 |
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81 :: |
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82 |
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83 B = array([[10, 11, 12, 13], |
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84 [20, 21, 22, 23], |
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85 [30, 31, 32, 33], |
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86 [40, 41, 42, 43]]) |
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87 |
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88 Obtain the elements, ``[[10, 13], [30, 33]]`` |
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89 |
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90 Answer: ``B[::2, ::3]`` |
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91 |
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92 #. What command is used to read an image file? |
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93 |
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94 a. imshow |
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95 #. imread |
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96 #. imopen |
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97 #. open |
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98 |
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99 Answer: ``imread`` |
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100 |
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101 #. If ``P`` is ``array([12, 13, 14, 15])`` then ``P.shape`` gives |
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102 ``(4, 1)``. True or False? |
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103 |
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104 Answer: False |
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105 |
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106 Larger Questions |
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107 ---------------- |
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108 |
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109 .. A minimum of 2 questions here (along with answers) |
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110 |
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111 1. Given the array, |
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112 :: |
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113 |
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114 B = array([[10, 11, 12, 13], |
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115 [20, 21, 22, 23], |
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116 [30, 31, 32, 33], |
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117 [40, 41, 42, 43]]) |
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118 |
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119 Change the array to |
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120 :: |
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121 |
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122 B = array([[10, 11, 10, 11], |
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123 [20, 21, 20, 21], |
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124 [10, 11, 10, 11], |
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125 [20, 21, 20, 21]]) |
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126 |
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127 using slicing and striding. |
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128 |
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129 Answer:: |
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130 |
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131 B[:2, 2:] = B[:2, :2] |
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132 B[2:, :2] = B[:2, :2] |
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133 B[2:, 2:] = B[:2, :2] |
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134 |
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135 #. Find out how to display a grayscale image with proper colors. Hint, |
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136 use ``?`` on ``imshow``. |
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137 |
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138 Answer: ``cmap=cm.gray`` |
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139 |
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140 #. From the image, ``tagore-einstein.png``, |
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141 a. show only the face of Einstein. |
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142 b. show only the face of Tagore. |
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143 |
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144 Hint, use ``imread`` to read the image and ``imshow`` to show the |
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145 image. Use ``cm.gray`` as ``cmap`` to display the image properly. |
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146 |
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147 Answer:: |
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148 |
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149 F = imread('tagore-einstein.png') |
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150 imshow(F[:210, 20:180], cmap=cm.gray) |
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151 |
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152 F = imread('tagore-einstein.png') |
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153 imshow(F[30:300, 320:480], cmap=cm.gray) |
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154 |
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155 .. #[Puneeth: This question contains answer to previous |
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156 .. question. Shouldn't be shown at the same time.] |
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157 |
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158 |
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159 |
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