Python

列表

list = []
list[i:j]  # returns list subset
list[-1]   # access last element
list[:-1]  # return all but the last element

list[i] = val
list[i:j] = otherlist  # replace ith to jth element with otherlist
del list[i:j]

list.append(item)
list.extend(list)
list.insert(0, item)
list.pop()
list.remove(i)
list1 + list2     # combine two list    
set(list)         # remove duplicate elements from a list

list.reverse()
list.count(item)
sum(list)

list.sort()

zip(list1, list2)
sorted(list)
",".join(list)

Dict

dict.keys()
dict.values()
"key" in dict
dict["key"]   # throws KeyError
dict.get("key")
dict.setdefault("key", 1)

迭代器

for item in ["a", "b", "c"]:
for i in range(4):     # 0 to 3
for i in range(4, 8):  # 4 to 7
for key, val in dict.items():

字符串

str[0:4]
len(str)

string.replace("-", " ")
",".join(list)
"hi {0}".format('j')
str.find(",")
str.index(",")   # same, but raises IndexError
str.count(",")
str.split(",")

str.lower()
str.upper()
str.title()

str.lstrip()
str.rstrip()
str.strip()

str.islower()

类型转换

int(str)
float(str)

列表解析

[fn(i) for i in list]            # .map
map(fn, list)                    # .map, returns iterator

filter(fn, list)                 # .filter, returns iterator
[fn(i) for i in list if i > 0]   # .filter.map

正则表达式

import re

re.match(r'^[aeiou]', str)
re.sub(r'^[aeiou]', '?', str)
re.sub(r'(xyz)', r'\1', str)

expr = re.compile(r'^...$')
expr.match(...)
expr.sub(...)