XSLT apply templates select condition on node list - xpath

Question

I have an xml with a list and wanted to apply template on that which will send only specific nodes by a condition, but it is applying on the whole list. Could someone if I am missing anything, I am relatively new to XSL.
The condition I wanted to apply is if dep is 7 and no city tag exists, I started with condition to check if dep is 7. After apply template if i print my list, it is getting all of them, Instead of dep just with value 7.In my output I expect not to have dep with value 9.
Input XML:
<employeeList>
<employee>
<dep>7</dep>
<salary>900</salary>
</employee>
<employee>
<dep>7</dep>
<city>LA</city>
<salary>500</salary>
</employee>
<employee>
<dep>9</dep>
<salary>600</salary>
</employee>
<employee>
<dep>7</dep>
<salary>800</salary>
</employee>
</employeeList>
My XSL:
<xsl:apply-templates select="employeeList[employee/dep = '7']" mode="e"/>
<xsl:template match="employeeList" mode="e">
<xsl:for-each select="employee">
<dep>
<xsl:value-of select="dep" />
</dep>
</xsl:for-each>
Output XML:
<dep>7</dep><dep>7</dep><dep>9</dep><dep>7</dep>

Answer 1

The condition I wanted to apply is if dep is 7 and no city tag exists
Such condition can be easily implemented using e.g.:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/employeeList">
<root>
<xsl:for-each select="employee[dep='7' and not(city)]">
<dep>7</dep>
</xsl:for-each>
</root>
</xsl:template>
</xsl:stylesheet>
Or shortly:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/employeeList">
<root>
<xsl:copy-of select="employee[dep='7' and not(city)]/dep"/>
</root>
</xsl:template>
</xsl:stylesheet>
But it's hard to see the point in outputting X number of <dep>7</dep> elements.

Answer 2

You select the employeeList based on a condition on its employee/dep, but once you have selected it, that condition no longer matters, and the <xsl:for-each select="employee"> selects all employees, regardless of their dep.
You can repeat the condition in the xsl:for-each statement:
<xsl:for-each select="employee[dep = '7']">