我遇到了来自freeCodeCamp的编码挑战Spinal Tap Case。基本上我不知道如何执行最后一次检查。
这是最后一次检查：
localStorage
这是我的代码：
spinalCase("AllThe-small Things") should return "all-the-small-things"我确实认识到最后function spinalCase(str) {
var outputString,
newstr,
pattern1 = new RegExp(/[_\s]/, 'g'),
pattern2 = new RegExp(/(?=[A-Z])/, 'g'),
stringTest1 = pattern1.test(str),
stringTest2 = pattern2.test(str);
if(stringTest1) {
outputString = str.replace(pattern1, '-');
newstr = outputString.toLowerCase();
} else if(stringTest2) {
str.split(/(?=[A-Z])/).join(' ');
outputString = str.replace(pattern2, '-');
newstr = outputString.toLowerCase();
} else if (stringTest1 && stringTest2){
outputString = str.replace(pattern1, '-');
outputString = str.replace(pattern2, '-');
newstr = outputString.toLowerCase();
}
return newstr;
}
条件应该先行，但我没有正确的语法。
提前致谢！
答案 0 :(得分：4)
这是我的解决方案，简单使用正则表达式，适用于所有情况
function spinalCase(str) {
return str.replace(/([A-Z])/g,' $1') /*Find all cap and add space at the start*/
.replace(/[^A-Za-z0-9]/g,' ') /*Find all non alpha numeric and replace it with space*/
.replace(/\s{1,}/g,"-") /*Convert all spaces to -*/
.replace(/^\-|[\-]$/g,'') /*Slice - at the start and end*/
.toLowerCase(); /*LowerCase it*/
}
答案 1 :(得分：3)
以下是我推荐的方法：
function sp(str) {
var spinal = str.replace(/(?!^)([A-Z])/g, ' $1')
.replace(/[_\s]+(?=[a-zA-Z])/g, '-').toLowerCase();
return spinal
}
就您的代码而言，请检查：
如果test1 else if test2，则else if test1 and test2，逻辑不正确：
您可以尝试向第一个添加!test2或!test1，如果检查可以使其正常工作：
if (stringTest1 && !stringTest2)...
编辑：
以下是如何让你的代码在最后的代码中触发，如果我在那里放一个console.log来向你展示：
function spinalCase(str) {
var outputString,
newstr,
pattern1 = new RegExp(/[_\s]/, 'g'),
pattern2 = new RegExp(/(?=[A-Z])/, 'g'),
stringTest1 = pattern1.test(str),
stringTest2 = pattern2.test(str);
if(stringTest1 && !stringTest2) {
outputString = str.replace(pattern1, '-');
newstr = outputString.toLowerCase();
} else if(!stringTest1 && stringTest1) {
str.split(/(?=[A-Z])/).join(' ');
outputString = str.replace(pattern2, '-');
newstr = outputString.toLowerCase();
} else if (stringTest1 && stringTest2){
console.log('were in the last else!!!');
outputString = str.replace(pattern1, '-');
outputString = str.replace(pattern2, '-');
newstr = outputString.toLowerCase();
}
return newstr;
}
答案 2 :(得分：1)
这是我的解决方案，对正则表达式的重视程度稍低：
function spinalCase(str) {
var newStr = str[0];
for (var j = 1; j < str.length; j++) {
// if not a letter make a dash
if (str[j].search(/\W/) !== -1 || str[j] === "_") {
newStr += "-";
}
// if a Capital letter is found
else if (str[j] === str[j].toUpperCase()) {
// and preceded by a letter or '_'
if (str[j-1].search(/\w/) !== -1 && str[j-1] !== "_") {
// insert '-' and carry on
newStr += "-";
newStr += str[j];
}
else {
newStr += str[j];
}
}
else {
newStr += str[j];
}
}
newStr = newStr.toLowerCase();
return newStr;
}
答案 3 :(得分：1)
function spinalCase(str) {
// any string followed by upperCase letter
var re = /(?=[A-Z])/g;
// any string followed by space and upperCase/lowerCase letter
var re2=/(?=\s[A-Z]|\s[a-z])/g;
// any string of 2 or more '-'
var re3 = new RegExp("-{2,}", "g");
var space = new RegExp(" ","g");
var hyphen = new RegExp("_","g");
str = str.replace(hyphen,"-");
str = str.replace(re, '-');
str = str.replace(re2,"-");
str = str.replace(re3,"-");
str = str.replace(space,"");
str = str.toLowerCase();
if(str.slice(0,1)== '-'){
str = str.replace("-","");
}
return str;
}
spinalCase('This Is Spinal Tap');
答案 4 :(得分：1)
function spinalCase(str) {
var newStr = '';
var arr = str.split('');
for (var i = 0; i < arr.length; i += 1) {
if (i > 0) {
if (arr[i] >= 'A' && arr[i] <= 'Z') {
if (arr[i - 1] >= 'a' && arr[i - 1] <= 'z') {
newStr += '-';
newStr += arr[i].toLowerCase();
continue;
}
}
else if (arr[i] === ' ' || arr[i] === '_') {
newStr += '-';
continue;
}
}
newStr += arr[i].toLowerCase();
}
return newStr;
}
spinalCase("AllThe-small Things");
答案 5 :(得分：1)
function spinalCase(str) {
//Split the string at one of the following conditions
//a whitespace character [\s] is encountered
//underscore character [_] is encountered
//or by an uppercase letter [(?=[A-Z])]
//Join the array using a hyphen (-)
//Lowercase the whole resulting string
return str.split(/\s|_|(?=[A-Z])/).join('-').toLowerCase();
}
答案 6 :(得分：1)
我也坚持这样做，但是找到了一个更简单的解决方案：
import numpy as np
from numba import njit, prange
dtype_complex = np.complex64
@njit
def _perm(matrix):
n = matrix.shape[0]
d = np.ones(n, dtype=dtype_complex)
j = 0
s = 1
f = np.arange(n)
v = matrix.sum(axis=0)
p = np.prod(v)
while (j < n - 1):
v -= 2 * d[j]*matrix[j]
d[j] = -d[j]
s = -s
prod = np.prod(v)
p += s * prod
f[0] = 0
f[j] = f[j+1]
f[j+1] = j + 1
j = f[0]
return p / 2 ** (n - 1)
@njit
def _get_elements(one_over_det, matrix, lefts, rights):
length = len(lefts)
to_perm = np.zeros((length, length), dtype=dtype_complex)
for idx1, lbit_idx1 in enumerate(lefts):
for idx2, lbit_idx2 in enumerate(rights):
to_perm[idx1, idx2] = one_over_det * matrix[lbit_idx2, lbit_idx1]
return _perm(to_perm)
@njit
def _get_result(t, L, B, ener, evec, f_mat, I, site1, site2):
result = 0.0 + 0.0j
for a in np.arange(L):
for b in np.arange(L):
for e in np.arange(L):
for f in np.arange(L):
H_abef = 2 * (B[:,a] - B[:,b] + B[:,e] - B[:,f])
f_exp_H_abef_t = f_mat @ (np.diag(np.exp(1j * H_abef * t)).astype(dtype_complex))
to_inv = I + f_mat - f_exp_H_abef_t
inv = np.linalg.inv(to_inv)
one_over_det = 1.0 / np.linalg.det(to_inv)
matrix = f_exp_H_abef_t @ inv
phase1 = np.exp(1j * (
ener[a] - ener[b] + ener[e] - ener[f]
- B[a, a] - B[b, b] - B[e, e] - B[f, f]
+ 2 * (
+ B[a, b] + B[e, f]
+ B[f, a] + B[f, b]
- B[e, a] - B[e, b]
)
) * t)
for c in np.arange(L):
for d in np.arange(L):
phase2 = np.exp(2j * (
B[f, c] + B[f, d] - B[e, c] - B[e, d]
) * t)
for g in np.arange(L):
for h in np.arange(L):
# 8th order term
elements = _get_elements(one_over_det, matrix, [a, c, e, g], [b, d, f, h])
# 6th order terms
if b == c: elements += _get_elements(one_over_det, matrix, [a, e, g], [d, f, h])
if d == e: elements += _get_elements(one_over_det, matrix, [a, c, g], [b, f, h])
if b == e: elements += _get_elements(one_over_det, matrix, [a, c, g], [d, f, h])
if f == g: elements += _get_elements(one_over_det, matrix, [a, c, e], [b, d, h])
if d == g: elements += _get_elements(one_over_det, matrix, [a, c, e], [b, f, h])
if b == g: elements += _get_elements(one_over_det, matrix, [a, c, e], [d, f, h])
# quartic terms
if b == e and f == g: elements += _get_elements(one_over_det, matrix, [a, c], [d, h])
if b == e and d == g: elements += _get_elements(one_over_det, matrix, [a, c], [f, h])
if b == c and f == g: elements += _get_elements(one_over_det, matrix, [a, e], [d, h])
if b == c and d == g: elements += _get_elements(one_over_det, matrix, [a, c], [f, h])
if d == e and f == g: elements += _get_elements(one_over_det, matrix, [a, c], [b, h])
if b == c and d == e: elements += _get_elements(one_over_det, matrix, [a, g], [f, h])
if d == e and b == g: elements += _get_elements(one_over_det, matrix, [a, c], [f, h])
# quadratic term
if b == c and d == e and f == g: elements += one_over_det * matrix[h, a]
unitary = evec[site2, a] * evec[site2, b] \
* evec[site1, c] * evec[site1, d] \
* evec[site2, e] * evec[site2, f] \
* evec[site1, g] * evec[site1, h]
result += unitary * phase1 * phase2 * elements
return result
答案 7 :(得分：1)
初学者友好的解决方案：
function spinalCase(str) {
//change camelCase to title case(i.e. change 'markIsHere' to 'Mark Is Here')
let newStr = str.replace(/([a-z])([A-Z])/g, ('$1 $2'));
//replace space with '-'
newStr = newStr.replace(/ /g, '-');
//replace underscores with '-'
newStr = newStr.replace(/_/g,'-');
//change the result to lowercase
return newStr.toLowerCase()
}
答案 8 :(得分：0)
function spinalCase(str) {
// Create a variable for the white space and underscores
var regex = /\s+|_+/g;
// Replace low-upper case to low-space-uppercase
str = str.replace(/([a-z])([A-Z])/g, '$1 $2');
// Replace space and underscore with dashes
return str.replace(regex, '-').toLowerCase();
}
答案 9 :(得分：0)
function insert(arr){
arr = arr.split("");
for(let i in arr){
if (/[A-Z]/.test(arr[i])&& i>0){
arr[i] = "-" + arr[i];
}
}
arr = arr.join("");
return arr;
}
function spinalCase(str) {
str = str.split(/\s+|_/);
str = str.map(item=>insert(item));
str = str.join("-");
str = str.toLowerCase();
return str;
}