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浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
浅析为什么char类型的范围是 -128~+127在C语言中， signed char 类型的范围为-128~127,每本教科书上也这么写，但是没有哪一本书上（包括老师）也不会给你为什么是-128~127，这...在C语言中， signed char 类型的范围为-128~127,每本教科书上...
Selecting/excluding sets of columns in pandas [duplicate]
...passed as argument removed.
Here, the result is used to remove columns B and D from df:
df2 = df[df.columns.difference(['B', 'D'])]
Note that it's a set-based method, so duplicate column names will cause issues, and the column order may be changed.
Advantage over drop: you don't create a cop...
How to find the 'sizeof' (a pointer pointing to an array)?
...pointing to. There are tricks, like ending the array with a known out-of-band value and then counting the size up until that value, but that's not using sizeof().
Another trick is the one mentioned by Zan, which is to stash the size somewhere. For example, if you're dynamically allocating the a...
List columns with indexes in PostgreSQL
... uk_test3c unique (c),constraint uk_test3ab unique (a, b));
List indexes and columns indexed:
select
t.relname as table_name,
i.relname as index_name,
a.attname as column_name
from
pg_class t,
pg_class i,
pg_index ix,
pg_attribute a
where
t.oid = ix.indrelid
an...
Can I define a class name on paragraph using Markdown?
...values with Markdown Extra through.
You can use regular HTML if you like, and add the attribute markdown="1" to continue markdown-conversion within the HTML element. This requires Markdown Extra though.
<p class='specialParagraph' markdown='1'>
**Another paragraph** which allows *Markdown* w...
Bitwise operation and usage
...ators that work on multi-bit values, but conceptually one bit at a time.
AND is 1 only if both of its inputs are 1, otherwise it's 0.
OR is 1 if one or both of its inputs are 1, otherwise it's 0.
XOR is 1 only if exactly one of its inputs are 1, otherwise it's 0.
NOT is 1 only if its input is 0, o...
How do I list all files of a directory?
How can I list all files of a directory in Python and add them to a list ?
21 Answers
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How do I round a decimal value to 2 decimal places (for output on a page)
...mal currently with .ToString() , it's accurate to like 15 decimal places, and since I'm using it to represent dollars and cents, I only want the output to be 2 decimal places.
...
What is the optimal Jewish toenail cutting algorithm?
...automatically trim toenails, so that users can simply put their feet in it and run it instead of having to manually do it by biting them or using nail clippers.
...
How do I loop through a list by twos? [duplicate]
I want to loop through a Python list and process 2 list items at a time. Something like this in another language:
7 Answers...