Python|检查给定字符串是否为二进制字符串

给定一个字符串str。任务是检查它是否是二进制字符串。
例子：

Input: str = "01010101010"
Output: Yes

Input: str = "geeks101"
Output: No

方法一：使用集合

1. 在集合中插入给定的字符串
2. 检查设置的字符是否仅由 1 和/或 0 组成。

Python3

# Python program to check
# if a string is binary or not
 
# function for checking the
# string is accepted or not
def check(string) :
 
    # set function convert string
    # into set of characters .
    p = set(string)
 
    # declare set of '0', '1' .
    s = {'0', '1'}
 
    # check set p is same as set s
    # or set p contains only '0'
    # or set p contains only '1'
    # or not, if any one condition
    # is true then string is accepted
    # otherwise not .
    if s == p or p == {'0'} or p == {'1'}:
        print("Yes")
    else :
        print("No")
 
 
         
# driver code
if __name__ == "__main__" :
 
    string = "101010000111"
 
    # function calling
    check(string)

输出

Yes

方法 2：简单迭代

1. 对每个字符进行迭代并检查该字符是 0 还是 1。
2. 如果不是，则设置一个计数器并中断。
3. 迭代后检查计数器是否设置。

Python3

# Python program to check
# if a string is binary or not
 
# function for checking the
# string is accepted or not
def check2(string) :
 
    # initialize the variable t
    # with '01' string
    t = '01'
 
    # initialize the variable count
    # with 0 value
    count = 0
 
    # looping through each character
    # of the string .
    for char in string :
 
        # check the character is present in
        # string t or not.
        # if this condition is true
        # assign 1 to the count variable
        # and break out of the for loop
        # otherwise pass
        if char not in t :
            count = 1
            break
        else :
            pass
         
    # after coming out of the loop
    # check value of count is non-zero or not
    # if the value is non-zero the en condition is true
    # and string is not accepted
    # otherwise string is accepted
    if count :
        print("No")
    else :
        print("Yes")
 
 
 
# driver code
if __name__ == "__main__" :
 
    string = "001021010001010"
 
    # function calling
    check2(string)

输出

No

方法 3 ：正则表达式

1. 使用 compile() 为“字符不是 0 或 1”编译正则表达式。
2. 使用 re.findall() 获取满足上述正则表达式的字符串。
3. 根据结果打印输出。

Python3

#import library
import re
 
sampleInput = "1001010"
 
# regular expression to find the strings
# which have characters other than 0 and 1
c = re.compile('[^01]')
 
# use findall() to get the list of strings
# that have characters other than 0 and 1.
if(len(c.findall(sampleInput))):
    print("No") # if length of list > 0 then it is not binary
else:
    print("Yes") # if length of list = 0 then it is binary

输出

Yes