Python Common built-in function summary _python

First, mathematics related

1, Absolute Value: ABS (-1)
2, the maximum minimum value: Max ([1,2,3]), MIN ([1,2,3])
3, Sequence length: Len (' abc '), Len ([1,2,3]), Len ((1,2,3))
4, take the mold: Divmod (5,2)//(2,1)
5, the Powers: Pow (2,3,4)//2**3/4
6, Floating Points: round (1)//1.0

Second, function-related

1, whether the function can be called: callable (funcname), note that funcname variable to define
2. Type judgment: Isinstance (X,list/int)
3. Comparison: CMP (' hello ', ' hello ')
4. Fast generation Sequence: (x) range ([Start,] stop[, step])

Third, type conversion

1, int (x)
2, Long (x)
3, float (x)
4, complex (x)//plural
5, str (x)
6, List (x)
7, tuple (x)//tuple
8, Hex (x)
9, Oct (x)
10, Chr (x)//return x corresponding character, such as Chr (65) return ' A '
11, Ord (x)//return character corresponding to the ASC code number number, such as Ord (' A ') return 65

Four, string processing

1, initial capital: Str.capitalize

Copy Code code as follows:

>>> ' Hello '. Capitalize ()

' Hello '
2. String Replacement: Str.replace

Copy Code code as follows:

>>> ' Hello '. Replace (' l ', ' 2 ')
' He22o '

You can pass three arguments, and the third parameter is the number of replacements

3. String cutting: Str.split

Copy Code code as follows:

>>> ' Hello '. Split (' L ')
[' He ', ', ', ' O ']

Can pass two parameters, the second parameter is the number of cuts

All three of these methods can be introduced into the string module and then invoked in a string.xxx manner.

V. Sequence processing functions

1. Len: Sequence length
2, Max: The maximum value in the sequence
3, min: Minimum value
4. Filter: Filtration Sequence

Copy Code code as follows:

>>> filter (lambda x:x%2==0, [1,2,3,4,5,6])
[2, 4, 6]

5, Zip: Parallel traversal

Copy Code code as follows:

>>> name=[' Jim ', ' Tom ', ' Lili '
>>> age=[20,30,40]
>>> tel=[' 133 ', ' 156 ', ' 189 ']
>>> Zip (Name,age,tel)
[(' Jim ', ' 156 '], (' Tom ', ', ') ', (' Lili ', 40, ' 189 ')]

Note that if the sequence length is not the same, it will be the following result:

Copy Code code as follows:

>>> name=[' Jim ', ' Tom ', ' Lili '
>>> age=[20,30,40]
>>> tel=[' 133 ', ' 170 ']
>>> Zip (Name,age,tel)
[(' Jim, ', '], (' Tom ', 30, ' 170 ')]

6, Map: Parallel traversal, can accept the parameters of a function type

Copy Code code as follows:

>>> a=[1,3,5]
>>> b=[2,4,6]
>>> Map (none,a,b)
[(1, 2), (3, 4), (5, 6)]
>>> map (Lambda x,y:x*y,a,b)
[2, 12, 30]

7. Reduce: Merge

Copy Code code as follows:

>>> L=range (1,101)
>>> L
[1, 2, 3, 4 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 , 34, 35.36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 64, 65 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 , 95, 96, 97, 98, 99, 100]
>>> reduce (lambda x,y:x+y,l)
5050