Regarding the question of python, good high reward

A score of 0 is also called a high reward. Too lazy.

ops[op] returns either add or sub, which is a method imported from the operator.

Therefore (*num) is to pass arguments to the method, and * means to pass in variadic parameters in order.

The value of ops is a function, that is, a function is executed.

Equivalent to if op =='add':

ans = add(*nums)

elif op == 'sub':

ans = sub(*nums)

The variable name is invalid and may have been entered by mistake.

Change the value of the environment variable from g: python python27 to g: python

After entering cmd into python, you will find the directory (g: python).

In the same way, after installing a third-party library, add g: python scripts to the environment variables.

Confirm that the directory is correct.

It doesn't matter if the input is case or not, win is not sensitive.

cmd needs to be closed and opened again.

It looks like g: python is fine, don't use python27 to praise you so much.

, key=none, reverse=false)

uminnum = li[0]

key=none, reverse=true)

umaxnum = li[0]

li is a list that stores this data in a list, and then sort() is used in the sorting method of the list.

key=none, reverse=false) can also be written, because that's what the original form of the sort() function is. The default is to sort in ascending order.

key=none, reverse=true) to change the reverse variable of sort() so that sort() sorts in descending order.

li[0] is the first element to be sequenced.

Example 1c is a list, and each element in the list is a tuple, e.g. c[0]=(0,9), c[1]=(1,8).

The function of the key is to specify the attribute in the element in the list to be sorted (in this case, c) as the basis for sorting.

In the above example, the key is an anonymous method, and c[i][0], and c[i][1] are used as the sorting basis, so there is this result.

The role of CMP is to specify the criteria for comparison, such as ascending, inverse, and so on.

The elements in Example 2L are tuples, and the CMP is used for L[I][1] and L[J][1], using the built-in CMP method to compare the sizes, and since L[I][1] is Int, they are finally sorted in ascending order.

You can consider an example where there is a class person with two properties, the role of the key is to specify the sorting by age or gender, and the role of the CMP is to specify the sorting criteria (e.g. ascending or descending when sorting by age, which gender comes first when sorting by gender).

Example 3 randint is used to randomly generate integers of a specified range, since the range here is 1 to 2, so randint always generates 1 or 2

So f randomly returns -1 and 1

If f is used as the CMP parameter, the out-of-order result is obtained.

The set mode prototype looks like this:

set_mode(resolution=(0,0), flags=0, depth=0)

So it should. ,450))

a=[[ for x in range(2000)] for y in range(2000)]

is a method.

After the execution, you can view len(a) len(a[0]) The result is 2000, if the data is not very dense, you can also use a dictionary instead, which can save space and achieve a similar effect, but pay attention to assign the value first and then reference, otherwise an error will be reported.

Weakly asked, what is "open"?

Agreed"sitanfufly";

Another:1This ** will be wrong when len(l)==1; Recommendation: while len(l) >1:

.2.l = l[1:] inside the loop is too inefficient when l may have a lot of data -- this is encountered in practice -- suggesting an adjustment approach.

front=l[0]

and l=l[1:].

Each cycle l becomes [2,3,4][3,4][4].

Looking for an element with a value of 4 starting with an index of 4, apparently finding the 5th (starting from 0) position 4.

Hello: The first parameter is the element you are looking for, which is who you want to find.

The second parameter is: start from that position (count from 0).

The third parameter is: the position of the end.