python题库生信

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laojean 2024-08-01 01:10:11

文章标签 python题库生信大数据编程语言机器学习数据挖掘 文章分类 Python 后端开发

1.原位替换

a = 5
b = 6
c = 7
a, b = b,a
print("a is",a)
print("b is",b)

a is 6
b is 5

a, (b,c) = c, (a,b)
print("a is",a)
print("b is",b)
print("c is",c)

a is 7
b is 6
c is 5

first, *middle_all, last = (1,2,3,4,5,6)
middle_all

[2, 3, 4, 5]

2.链似比较

x = 5
print("1 < x < 10 is", 1 < x < 10)
print("10 > x <= 9", 10 > x <= 9)

1 < x < 10 is True
10 > x <= 9 True

3. 列表索引，反序

a = [1,2,3,4,5]
a[::2]

[1, 3, 5]

a[::-1]

[5, 4, 3, 2, 1]

4. 列表解析、字典解析、元组解析

# 获得系列坐标点
a = ((i,j) for i in range(3) for j in range(2))
a

<generator object <genexpr> at 0x7fa8d04d7fc0>

for i in a:
    print(i)

(0, 0)
(0, 1)
(1, 0)
(1, 1)
(2, 0)
(2, 1)

str1 = "I love sheng xin bao dian"
print([i for i in str1.split() if i.endswith('n')])

['xin', 'dian']

a = {i:i*2 for i in range(5)}
a

{0: 0, 1: 2, 2: 4, 3: 6, 4: 8}

[(x, y) for x in range(4) if x % 2 == 1 for y in range(4)]

[(1, 0), (1, 1), (1, 2), (1, 3), (3, 0), (3, 1), (3, 2), (3, 3)]

5.集合操作

a = set(["sheng", "xin", "bao","dian","best","tutotials"])
b = set(["hong", "ji", "yin","zu","best","tutotials"])
a | b  # union

{'bao', 'best', 'dian', 'hong', 'ji', 'sheng', 'tutotials', 'xin', 'yin', 'zu'}

a & b # intersection

{'best', 'tutotials'}

a ^ b # Symmetric Difference

{'bao', 'dian', 'hong', 'ji', 'sheng', 'xin', 'yin', 'zu'}

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6.Negative round

print("round整数:",str(round(1234.5678, -2)))

print("round小数:",str(round(1234.5678, 2)))

round整数: 1200.0
round小数: 1234.57

7.多行字符串的优雅嵌套

# \可以，但是第二行需要起头
system_command = "s-plot pheatmap -f matrix \
-t heatmap -a TRUE"
print(system_command)

s-plot pheatmap -f matrix -t heatmap -a TRUE

# 字符串中包含换行符
# 切第二行要起头，不然会有较多空格
system_command = """s-plot pheatmap -f matrix
-t heatmap -a TRUE""" 
print(system_command)
print(system_command.replace('\n', ' '))

s-plot pheatmap -f matrix 
-t heatmap -a TRUE
s-plot pheatmap -f matrix  -t heatmap -a TRUE

# 类元组的写法，既可以跨行，又可以自由格式
# 需要注意2点
   # 类元组，无逗号
   # 字符串连接时不会自动加空格，空格需要保存在字符串里面 
system_command = ("s-plot pheatmap -f matrix "
                  "-t heatmap -a TRUE")
print(system_command)

s-plot pheatmap -f matrix -t heatmap -a TRUE

# 多一步join；
system_command = ["s-plot pheatmap -f matrix",
                  "-t heatmap -a TRUE"]
print(' '.join(system_command))

s-plot pheatmap -f matrix -t heatmap -a TRUE

8.zip转换两个列表为字典

keyL = [1,2,3]
valueL = ['a','b','v']
for i ,j in zip(keyL, valueL):
    print(i,j)

1 a
2 b
3 v

import pprint
pprint.pprint(dict(zip(keyL, valueL)))

{1: 'a', 2: 'b', 3: 'v'}

dict([(i,j) for i ,j in zip(keyL, valueL)])

{1: 'a', 2: 'b', 3: 'v'}

9.enumerate索引列表 (不再使用len)

a = ['s','x','b','d']

# Preferred way
for index, item in enumerate(a):
    print(index,item)

print("\n")

# Old way
for i in range(len(a)):
    print(i,a[i])

0 s
1 x
2 b
3 d


0 s
1 x
2 b
3 d

10.矩阵转置

a = [(1,2), (3,4), (5,6)]
b = zip(*a)
for i in b:
    print(i)

(1, 3, 5)
(2, 4, 6)

11.sum的另一用法，二维数组秒变1维

aList = [[1, 2, 3], [4, 5], [6], [7, 8, 9]]
sum(aList, [])

[1, 2, 3, 4, 5, 6, 7, 8, 9]

12.解释正则表达式

import re
re.compile("^[a-z]*$", re.DEBUG)

AT AT_BEGINNING
MAX_REPEAT 0 MAXREPEAT
  IN
    RANGE (97, 122)
AT AT_END

re.compile("^[a-z][0-9]+$", re.DEBUG)

AT AT_BEGINNING
IN
  RANGE (97, 122)
MAX_REPEAT 1 MAXREPEAT
  IN
    RANGE (48, 57)
AT AT_END

re.compile("^[a-z]([0-9]+)$", re.DEBUG)

AT AT_BEGINNING
IN
  RANGE (97, 122)
SUBPATTERN 1 0 0
  MAX_REPEAT 1 MAXREPEAT
    IN
      RANGE (48, 57)
AT AT_END

13.for..else;若for循环中未执行break,则else会被执行

found = False
for i in range(2,5):
    if i == 1:
        found = True
        break
if not found: 
    print("i was never 1")

i was never 1

for i in range(2,5):
    if i == 1:
        break
else:
    print("i was never 1")

i was never 1

14.启动网络服务器，用于文件预览或传输

# run in commang line
python -m http.server 8000
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...

15.python打印九九乘法表 (列表解析)

print('\n'.join([' '.join(['%s*%s=%-2s' % (y,x,x*y) for y in range(1,x+1)]) for x in range(1,10)]))

1*1=1 
1*2=2  2*2=4 
1*3=3  2*3=6  3*3=9 
1*4=4  2*4=8  3*4=12 4*4=16
1*5=5  2*5=10 3*5=15 4*5=20 5*5=25
1*6=6  2*6=12 3*6=18 4*6=24 5*6=30 6*6=36
1*7=7  2*7=14 3*7=21 4*7=28 5*7=35 6*7=42 7*7=49
1*8=8  2*8=16 3*8=24 4*8=32 5*8=40 6*8=48 7*8=56 8*8=64
1*9=9  2*9=18 3*9=27 4*9=36 5*9=45 6*9=54 7*9=63 8*9=72 9*9=81

16.map, filter

# 过滤大于4的元素
a = [3,4,5]
[i for i in a if i<4]

[3]

list(filter(lambda x: x<4, a))

[5]

# 每个元素加2
[i+2 for i in a]

[5, 6, 7]

map(lambda x: x+2, a)

<map at 0x7fa8d0502358>

list(map(lambda x: x+2, a))

[5, 6, 7]

算2的1000次方的各位数之和

sum(map(int, str(2**1000)))

17. python打印心型

print('\n'.join([''.join([('Love'[(x-y) % len('Love')] if ((x*0.05)**2+(y*0.1)**2-1)**3-(x*0.05)**2*(y*0.1)**3 <= 0 else ' ') for x in range(-30, 30)]) for y in range(30, -30, -1)]))

python题库生信_编程语言

18. python打印曼德勃罗集合

print('\n'.join([''.join(['*'if abs((lambda a:lambda z,c,n:a(a,z,c,n))(lambda s,z,c,n:z if n==0else s(s,z*z+c,c,n-1))(0,0.02*x+0.05j*y,40))<2 else' 'for x in range(-80,20)])for y in range(-20,20)]))

python题库生信_python题库生信_02