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while (1) Vs. for (;;) Is there a speed difference?
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20 Answers
20
Active
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How do I create an empty array/matrix in NumPy?
...w-by-row:
>>> import numpy
>>> a = numpy.zeros(shape=(5,2))
>>> a
array([[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.],
[ 0., 0.]])
>>> a[0] = [1,2]
>>> a[1] = [2,3]
>>> a
array([[ 1., 2.],
[ 2., 3.],
[ 0., 0.],
[ 0., ...
Adding new column to existing DataFrame in Python pandas
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24 Answers
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How to write inline if statement for print?
...on: statement
if condition:
block
if expression (introduced in Python 2.5)
expression_if_true if condition else expression_if_false
And note, that both print a and b = a are statements. Only the a part is an expression. So if you write
print a if b else 0
it means
print (a if b else 0)
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App Inventor 2 文本代码块 · App Inventor 2 中文网
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App Inventor 2 文本代码块
” “ (字符串)
合并字符串
求长度
是否为空
字符串比较(Ascii码比较) < > = ≠ Ascii码转换
删除空格
大写
小写
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Pythonic way to print list items
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227
Assuming you are using Python 3.x:
print(*myList, sep='\n')
You can get the same behavior o...
Get all unique values in a JavaScript array (remove duplicates)
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Command to get nth line of STDOUT
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Using sed, just for variety:
ls -l | sed -n 2p
Using this alternative, which looks more efficient since it stops reading the input when the required line is printed, may generate a SIGPIPE in the feeding process, which may in turn generate an unwanted error message:
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What is the difference between “def” and “val” to define a function
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329
Method def even evaluates on call and creates new function every time (new instance of Function...