# Unbrackable blanck

In the following code I am obliged to insert `/`

to inside my fonction to obtain the desired result.

```
nl=3 #nombre de contraintes
nc=4 #nombre de variables
ring=QQ
A=matrix(ring,nl,nc,[1.5,2,4,3,4,1,2,1,2,3,1,2])
b=vector(ring,[550,700,200])
c=vector(ring,[4,6,3,1])
### code ####
def simplex_tableau_sf(A, b, c,cond=1) :
# A matrice des contraintes
# b vecteur des contraintes
# c vecteur des paramètres de l'objectif
# 1 (défaut) tableau
I=identity_matrix(A.nrows())
L=block_matrix([[A,I]],subdivide=False)
L=L.augment(b)
n=A.nrows()
m=A.ncols()
z1=vector([0 for i in range(n+1)])
c=flatten(-c)
z1=flatten(z1)
zc=vector(c+z1)
L=matrix(L.rows()+[zc])
rows = list(L)
hr=['$x_{}$'.format(i) for i in range(0,nc+nl)]
hr=list('')+list(hr)+list('b')
hc=list('xc2')+['$x_{}$'.format(i) for i in range(4,7)]
t = table(rows, header_row=hr, header_column=hc, frame=True)
if cond == 1 :
return t
elif cond != 1 :
return L
```

So is there a blank which can be used as a string

Can you clarify? It is not clear what you are asking. In Python,

`' '`

is a blank string. In LaTeX,`'~'`

is a blank.John look the difference when I use

`hr=list('/')+list(hr)+list('b')`

,`hr=list(' ')+list(hr)+list('b')`

and`hr=list('/')+list(hr)+list('b')`

. The only case where I obtain a correct result is the first and I want to have a blanc space not a`\`

.What happens if you use

`' '`

rather than`''`

?Sorry John, I send the wrong code. I have changed it in the question. I hope now it is correct. My problem is only with the

`/`

. Now with`' '`

, it works. I don't know why earlier, I have a wrong result.Quick comment: you can replace

`elif cond != 1 :`

with`else:`