string methods

Combine 2 strings to hashmap

zip(s1, s2)
input: s1 = "abc", s2 = "xyz"
output: [('a', 'x'), ('b', 'y'), ('c', 'z')]

the 1st char index of string

strs.index('h')
input: strs = "hello"
output: 0

split string to list

strs.split()
input: strs = "hello world"
output: ['hello', 'world']
strs.split('/')
input: strs = "hello/world"
output: ['hello', 'world']

it can split by any character, by default is space

Count the char in string

str_count = collections.Counter(strs)

判断字符串的condition

• startswith
• python "hello".startswith("h")
• endswith
• python "hello".endswith("o")

iterate string

• 不需要用range，可以用slice

for string in strs[1:]:
    if string.startswith(strs[0]):
        continue
    else:
        return False
return True

reverse string

• 用slice, 返回新的list

strs = strs[::-1]

• 用reverse，返回None

strs = list(strs)
strs.reverse()
strs = "".join(strs)

remove space

• strip

"  hello  ".strip()

• lstrip

"  hello  ".lstrip()

split string to list

• split

"hello world".split()

join list to string

• join

" ".join(["hello", "world"])

replace

• replace

"hello world".replace("world", "python")

lower and upper

"HELLO WORLD".lower()
"hello world".upper()