How to strip off left side of binary number in Python?

I got this binary number 101111111111000

I need to strip off the 8 most significant bits and have 11111000 at the end.

I tried to make 101111111111000 << 8, but this results in 10111111111100000000000, it hasn't the same effect as >> which strips the lower bits. So how can this be done? The final result MUST BE binary type.

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

2

What do you mean by "binary type"? Python has no such type. Would an integer suffice?

– Rory Daulton
Nov 25 '18 at 22:39

"it hasn't the same effect as >> which strips the lower bits" is because >> does not "strip", but it shifts the bits. So it does have the same effect as <<, in the other direction.

– usr2564301
Nov 25 '18 at 22:40

Integers are binary yeah, but I'am working in the binary level, that's why i'am approaching it with binaries.

– Rodrigo Formighieri
Nov 25 '18 at 22:41

1

@Alnitak It would be more like I need the 8 lower significant bits of any binary number, doesnt matter the word length.

– Rodrigo Formighieri
Nov 25 '18 at 22:52

1

@RodrigoFormighieri that's a completely different (but far easier) question to answer. Your question would have made more sense if you had described what you wanted to retain rather than what you want to throw away.

– Alnitak
Nov 25 '18 at 23:00

|
show 1 more comment

I got this binary number 101111111111000

I need to strip off the 8 most significant bits and have 11111000 at the end.

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

2

What do you mean by "binary type"? Python has no such type. Would an integer suffice?

– Rory Daulton
Nov 25 '18 at 22:39

"it hasn't the same effect as >> which strips the lower bits" is because >> does not "strip", but it shifts the bits. So it does have the same effect as <<, in the other direction.

– usr2564301
Nov 25 '18 at 22:40

Integers are binary yeah, but I'am working in the binary level, that's why i'am approaching it with binaries.

– Rodrigo Formighieri
Nov 25 '18 at 22:41

1

@Alnitak It would be more like I need the 8 lower significant bits of any binary number, doesnt matter the word length.

– Rodrigo Formighieri
Nov 25 '18 at 22:52

1

@RodrigoFormighieri that's a completely different (but far easier) question to answer. Your question would have made more sense if you had described what you wanted to retain rather than what you want to throw away.

– Alnitak
Nov 25 '18 at 23:00

|
show 1 more comment

I got this binary number 101111111111000

I need to strip off the 8 most significant bits and have 11111000 at the end.

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

I got this binary number 101111111111000

I need to strip off the 8 most significant bits and have 11111000 at the end.

python binary

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

asked Nov 25 '18 at 22:35

Rodrigo Formighieri

1109

2

What do you mean by "binary type"? Python has no such type. Would an integer suffice?

– Rory Daulton
Nov 25 '18 at 22:39

"it hasn't the same effect as >> which strips the lower bits" is because >> does not "strip", but it shifts the bits. So it does have the same effect as <<, in the other direction.

– usr2564301
Nov 25 '18 at 22:40

Integers are binary yeah, but I'am working in the binary level, that's why i'am approaching it with binaries.

– Rodrigo Formighieri
Nov 25 '18 at 22:41

1

@Alnitak It would be more like I need the 8 lower significant bits of any binary number, doesnt matter the word length.

– Rodrigo Formighieri
Nov 25 '18 at 22:52

1

@RodrigoFormighieri that's a completely different (but far easier) question to answer. Your question would have made more sense if you had described what you wanted to retain rather than what you want to throw away.

– Alnitak
Nov 25 '18 at 23:00

|
show 1 more comment

2

What do you mean by "binary type"? Python has no such type. Would an integer suffice?

– Rory Daulton
Nov 25 '18 at 22:39

"it hasn't the same effect as >> which strips the lower bits" is because >> does not "strip", but it shifts the bits. So it does have the same effect as <<, in the other direction.

– usr2564301
Nov 25 '18 at 22:40

Integers are binary yeah, but I'am working in the binary level, that's why i'am approaching it with binaries.

– Rodrigo Formighieri
Nov 25 '18 at 22:41

1

@Alnitak It would be more like I need the 8 lower significant bits of any binary number, doesnt matter the word length.

– Rodrigo Formighieri
Nov 25 '18 at 22:52

1

@RodrigoFormighieri that's a completely different (but far easier) question to answer. Your question would have made more sense if you had described what you wanted to retain rather than what you want to throw away.

– Alnitak
Nov 25 '18 at 23:00

What do you mean by "binary type"? Python has no such type. Would an integer suffice?

– Rory Daulton
Nov 25 '18 at 22:39

"it hasn't the same effect as >> which strips the lower bits" is because >> does not "strip", but it shifts the bits. So it does have the same effect as <<, in the other direction.

– usr2564301
Nov 25 '18 at 22:40

Integers are binary yeah, but I'am working in the binary level, that's why i'am approaching it with binaries.

– Rodrigo Formighieri
Nov 25 '18 at 22:41

@Alnitak It would be more like I need the 8 lower significant bits of any binary number, doesnt matter the word length.

– Rodrigo Formighieri
Nov 25 '18 at 22:52

@RodrigoFormighieri that's a completely different (but far easier) question to answer. Your question would have made more sense if you had described what you wanted to retain rather than what you want to throw away.

– Alnitak
Nov 25 '18 at 23:00

|
show 1 more comment

3 Answers
3

active

oldest

votes

You can get the rightmost 8 bits of an integer n using bitwise-and:

n&255

255 is the sum of the values of the smallest 8 bits.

So, starting with 101111111111000, which is 24568 decimal, n&255 gives 11111000, which is 248 decimal.

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

add a comment |

another general way to do this is:

n = int('101111111111000', 2) # 24568



n & (1 << int.bit_length(n) - 8) - 1

gives 120 (or 1111000)

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

add a comment |

To achieve this for a number x with n digits, one can use this

x&(2**(len(bin(x))-2-8)-1)

-2 to strip 0b, -8 to strip leftmost

Simply said it ands your number with just enough 1s that the 8 leftmost bits are set to 0.

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

add a comment |

Your Answer

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});

}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53472702%2fhow-to-strip-off-left-side-of-binary-number-in-python%23new-answer', 'question_page');
}
);

Post as a guest

Name

Required, but never shown

3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

You can get the rightmost 8 bits of an integer n using bitwise-and:

n&255

255 is the sum of the values of the smallest 8 bits.

So, starting with 101111111111000, which is 24568 decimal, n&255 gives 11111000, which is 248 decimal.

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

add a comment |

You can get the rightmost 8 bits of an integer n using bitwise-and:

n&255

255 is the sum of the values of the smallest 8 bits.

So, starting with 101111111111000, which is 24568 decimal, n&255 gives 11111000, which is 248 decimal.

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

add a comment |

You can get the rightmost 8 bits of an integer n using bitwise-and:

n&255

255 is the sum of the values of the smallest 8 bits.

So, starting with 101111111111000, which is 24568 decimal, n&255 gives 11111000, which is 248 decimal.

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

You can get the rightmost 8 bits of an integer n using bitwise-and:

n&255

255 is the sum of the values of the smallest 8 bits.

So, starting with 101111111111000, which is 24568 decimal, n&255 gives 11111000, which is 248 decimal.

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

edited Nov 25 '18 at 22:44

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

answered Nov 25 '18 at 22:38

khelwood

31.6k74365

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

add a comment |

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

this is only consistent with the OP's question if the input data had 16 bits to start with.

– Alnitak
Nov 25 '18 at 22:44

Well possibly. The OP said they wanted to strip the first 8 bits off a 15 bit number, but the output they asked for was 8 bits, so it doesn't seem like that was quite what they wanted.

– khelwood
Nov 25 '18 at 22:49

add a comment |

another general way to do this is:

n = int('101111111111000', 2) # 24568



n & (1 << int.bit_length(n) - 8) - 1

gives 120 (or 1111000)

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

add a comment |

another general way to do this is:

n = int('101111111111000', 2) # 24568



n & (1 << int.bit_length(n) - 8) - 1

gives 120 (or 1111000)

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

add a comment |

another general way to do this is:

n = int('101111111111000', 2) # 24568



n & (1 << int.bit_length(n) - 8) - 1

gives 120 (or 1111000)

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

another general way to do this is:

n = int('101111111111000', 2) # 24568



n & (1 << int.bit_length(n) - 8) - 1

gives 120 (or 1111000)

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

answered Nov 25 '18 at 23:18

Sam Mason

3,34711331

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

add a comment |

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

Also works! Thanks

– Rodrigo Formighieri
Nov 26 '18 at 12:43

add a comment |

To achieve this for a number x with n digits, one can use this

x&(2**(len(bin(x))-2-8)-1)

-2 to strip 0b, -8 to strip leftmost

Simply said it ands your number with just enough 1s that the 8 leftmost bits are set to 0.

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

add a comment |

To achieve this for a number x with n digits, one can use this

x&(2**(len(bin(x))-2-8)-1)

-2 to strip 0b, -8 to strip leftmost

Simply said it ands your number with just enough 1s that the 8 leftmost bits are set to 0.

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

add a comment |

To achieve this for a number x with n digits, one can use this

x&(2**(len(bin(x))-2-8)-1)

-2 to strip 0b, -8 to strip leftmost

Simply said it ands your number with just enough 1s that the 8 leftmost bits are set to 0.

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

To achieve this for a number x with n digits, one can use this

x&(2**(len(bin(x))-2-8)-1)

-2 to strip 0b, -8 to strip leftmost

Simply said it ands your number with just enough 1s that the 8 leftmost bits are set to 0.

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

answered Nov 25 '18 at 23:05

Jonathan R

1,142512

add a comment |

draft saved

draft discarded

Thanks for contributing an answer to Stack Overflow!

Please be sure to answer the question. Provide details and share your research!

But avoid …

Asking for help, clarification, or responding to other answers.

Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Post as a guest

Name

Required, but never shown

Name

Required, but never shown

Name

Required, but never shown

This page is only for reference, If you need detailed information, please check here

搜尋此網誌

Tukukkk