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POhow to change values in a nested list depending on elements of two other different lists and function is difficult to read
 

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  1. POhow to change values in a nested list depending on elements of two other different lists and function is difficult to read
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    <p>objective of the function is to change the elements of this</p> <pre><code>image=[[(15,103,225), (0,3,19)], [(22,200,1), (8,8,8)], [(0,0,0), (5,123,19)]] </code></pre> <p>into this with encode(nested, message)</p> <pre><code>&gt;&gt;&gt;encode(image,'hello) [[(14, 103, 255), (0, 3, 18)], [(22, 200, 0), (9, 9, 8)], [(0, 1, 0), (5, 122, 19)]] </code></pre> <p>each character in the message is converted into it's corresponding ascii thing and then each ascii thing is changed into 8-digit, base-two numbers. got that covered.</p> <p>now, to change the list like the above, what i have is:</p> <pre><code>def char_to_bits(char): """char_to_bits(char) -&gt; string Convert the input ASCII character to an 8 bit string of 1s and 0s. &gt;&gt;&gt; char_to_bits('A') '01000001' """ result = '' char_num = ord(char) for index in range(8): result = get_bit(char_num, index) + result return result def get_bit(int, position): """get_bit(int, position) -&gt; bit Return the bit (as a character, '1' or '0') from a given position in a given integer (interpreted in base 2). The least significant bit is at position 0. The second-least significant bit is at position 1, and so forth. &gt;&gt;&gt; for pos in range(8): ... print(b.get_bit(167, pos)) ... 1 1 1 0 0 1 0 1 """ if int &amp; (1 &lt;&lt; position): return '1' else: return '0' def message_to_bits(message): if len(message)==0: return '' for m in message: return "".join("".join(str(bits.char_to_bits(m)))for m in message) def set_bit_on(int, position): """set_bit_on(int, position) -&gt; int Set the bit at a given position in a given integer to 1, regardless of its previous value, and return the new integer as the result. The least significant bit is at position 0. The second-least significant bit is at position 1, and so forth. &gt;&gt;&gt; set_bit_on(0, 0) 1 &gt;&gt;&gt; set_bit_on(0, 1) 2 &gt;&gt;&gt; set_bit_on(167, 3) 175 """ return int | (1 &lt;&lt; position) def set_bit_off(int, position): """set_bit_off(int, position) -&gt; int Set the bit at a given position in a given integer to 0, regardless of its previous value, and return the new integer as the result. The least significant bit is at position 0. The second-least significant bit is at position 1, and so forth. &gt;&gt;&gt; set_bit_off(0, 0) 0 &gt;&gt;&gt; set_bit_off(1, 0) 0 &gt;&gt;&gt; set_bit_off(167, 0) 166 &gt;&gt;&gt; set_bit_off(175, 3) 167 """ return int &amp; ~(1 &lt;&lt; position) def set_bit(int, bit, position): """set_bit(int, bit, position) -&gt; int Set the bit at a given position to the given bit (as a char, either '1' or '0') regardless of its previous value, and return the new integer as the result. The least significant bit is at position 0. The second-least significant bit is at position 1, and so forth. &gt;&gt;&gt; set_bit(0, '1', 0) 1 &gt;&gt;&gt; set_bit(0, '1', 1) 2 &gt;&gt;&gt; set_bit(0, '1', 2) 4 &gt;&gt;&gt; set_bit(0, '1', 3) 8 &gt;&gt;&gt; set_bit(175, '0', 3) 167 &gt;&gt;&gt; set_bit(175, '1', 3) 175 """ if bit == '1': return set_bit_on(int, position) else: return set_bit_off(int, position)​ from collections import Iterable def flatten(nested): for item in nested: if isinstance(item, Iterable) and not isinstance(item, basestring): for x in flatten(item): yield x else: yield item def encode(nested, message): position= 0 fnested= list(flatten(nested)) bitlist= list("".join("".join(str(bits.char_to_bits(m)))for m in message)) for int in fnested: for bit in bitlist: return "".join("".join(("".join(str(bits.set_bit(int,bit,position)))for int in fnested)) for bit in bitlist) </code></pre> <p>the encode returns a string of length 1200 which is an epic failure and it looks very non-user-friendly.</p> <p>please help</p>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
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    1. UShwang hyungchae
    1. UShwang hyungchae
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    1. PO
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    1. This table or related slice is empty.
    1. COCan you explain more how the numbers change? I don't get it why `(14, 103, 255)` is kept but `(0, 3, 19)` is changed into `(0, 3, 18)`.
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      1. POhow to change values in a nested list depending on elements of two other different lists and function is difficult to read
      1. USjusthalf
    2. COthe function message_to_bits change the message ('hello') into binary. these binary stuff are the bits in functions set_bit, and encode. the binary of 'hello' is'0110100001100101011011000110110001101111'. position is always 0. int is the elements in image. so set_bit(15,'0',0) returns 14. set_bit(19,'0',0) returns 18. the int is converted into 8 digit binary and its last digit is changed into bit and the new 8 digit binary is changed into a base10 number and returned. the 1st element of the tuple has the bit of the 1st digit of the message's binary. 2nd in tuple, 2nd in binary, etc.
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      1. POhow to change values in a nested list depending on elements of two other different lists and function is difficult to read
      1. UShwang hyungchae
 

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