Question

我需要它做家庭作业，我们有一位新老师说我们应该谷歌但我没有找到有用的答案。

我尝试转换例如：a =“546”到a = 546，没有任何库函数

提前感谢您的帮助！

Answer 1

＆＃34;最纯粹的＆＃34;我能想到：

>>> a = "546"
>>> result = 0
>>> for digit in a:
        result *= 10
        for d in '0123456789':
            result += digit > d

>>> result
546

如果允许，请使用@ Ajax1234的字典构思：

>>> a = "546"
>>> value = {'0':0, '1':1, '2':2, '3':3, '4':4, '5':5, '6':6, '7':7, '8':8, '9':9}
>>> result = 0
>>> for digit in a:
        result = 10 * result + value[digit]

>>> result
546

Answer 2

您可以保留一个存储数字键的字符串和整数值的字典，然后迭代字符串。迭代字符串时，您可以使用enumerate来跟踪索引，然后将10增加到该幂减1，然后乘以字典中的相应键：

a = "546"
length = 0
for i in a:
   length += 1
d = {'1': 1, '0': 0, '3': 3, '2': 2, '5': 5, '4': 4, '7': 7, '6': 6, '9': 9, '8': 8}
count = 0
counter = 0
for i in a:
   count += (10**(length-counter-1)*d[i])
   counter += 1
print(count)

输出：

Answer 3

诀窍是546 = 500 + 40 + 6或5*10^2 + 4*10^1 + 6*10^0。

注意指数只是索引（反向）。使用它，您可以将此方法概括为函数：

def strToInt(number):
    total = 0                             # this is where we accumulate the result
    pwr = len(number) - 1                 # start the exponent off as 2
    for digit in number:                  # digit is the str "5", "4", and "6"
        digitVal = ord(digit) - ord('0')  # using the ascii table, digitVal is the int value of 5,4, and 6.
        total += digitVal * (10 ** pwr)   # add 500, then 40, then 6
        pwr -= 1                          # make sure to drop the exponent down by one each time
    return total

你可以像这样使用它：

>>> strToInt("546")
546

Answer 4

def stringToInt(s):
    result = 0
    value = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9}
    for digit in s:
        result = 10 * result + value[digit]

    return result

Answer 5

您可以循环使用字符串并使用ord对每个字符执行操作。

示例：

a="546"
num=0
for i in a:
     num = num * 10 + ord(i) - ord('0')

Answer 6

<script language="JavaScript">
 function toggle(source) {
  checkboxes = document.getElementsByName('foo');
  for(var i=0, n=checkboxes.length;i<n;i++) {
    checkboxes[i].checked = source.checked;
  }
}
</script>

<input type="checkbox" onClick="toggle(this)" /> Toggle All<br/>

<input type="checkbox" name="foo" value="bar1"> Monday<br/>
<input type="checkbox" name="foo" value="bar2"> Tuesday<br/>
<input type="checkbox" name="foo" value="bar3"> Everyday<br/>
<input type="checkbox" name="foo" value="bar4"> Days that don't end in 'Y'<br/>

Answer 7

def int(a):
ty = a.__class__.__name__
out = 0
di = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4,
      '5': 5, '6': 6, '7': 7, '8': 8, '9': 9}
if ty not in ("str", "int", "float", "bytes"):
    raise TypeError("unsupported format")
if a.__class__ == float:
    return a.__floor__()
elif a.__class__ == int:
    return a
else:
    ind = 0
    for val in a[::-1]:
        if val not in di:
            raise ValueError("invalid input")
        out += di[val]*(10**ind)
        ind += 1
        #print(out, di[val])
    return out

print(int("55"))
55

如何在不使用Python

7 个答案: